diff --git a/compiler/fir/resolve/testData/resolve/cfg/binaryOperations.dot b/compiler/fir/resolve/testData/resolve/cfg/binaryOperations.dot
index 1c8c05c2291..7ee0e47d9b4 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/binaryOperations.dot
+++ b/compiler/fir/resolve/testData/resolve/cfg/binaryOperations.dot
@@ -1,8 +1,8 @@
 digraph binaryOperations_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph test_1 {
-  0 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  0 [shape=box label="Enter function test_1" style="filled"];
   1 [shape=box label="Enter block"];
   2 [shape=box label="Enter when"];
   3 [shape=box label="Enter when branch condition "];
@@ -23,7 +23,7 @@ subgraph test_1 {
   18 [shape=box label="Exit when branch result"];
   19 [shape=box label="Exit when"];
   20 [shape=box label="Exit block"];
-  21 [shape=box label="Exit function test_1"];
+  21 [shape=box label="Exit function test_1" style="filled"];
 
   0 -> {1};
   1 -> {2};
@@ -48,8 +48,8 @@ subgraph test_1 {
   20 -> {21};
 }
 
-subgraph test_2 {
-  22 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  22 [shape=box label="Enter function test_2" style="filled"];
   23 [shape=box label="Enter block"];
   24 [shape=box label="Enter when"];
   25 [shape=box label="Enter when branch condition "];
@@ -70,7 +70,7 @@ subgraph test_2 {
   40 [shape=box label="Exit when branch result"];
   41 [shape=box label="Exit when"];
   42 [shape=box label="Exit block"];
-  43 [shape=box label="Exit function test_2"];
+  43 [shape=box label="Exit function test_2" style="filled"];
 
   22 -> {23};
   23 -> {24};
@@ -95,8 +95,8 @@ subgraph test_2 {
   42 -> {43};
 }
 
-subgraph test_3 {
-  44 [shape=box label="Enter function test_3"];
+subgraph cluster_test_3 {
+  44 [shape=box label="Enter function test_3" style="filled"];
   45 [shape=box label="Enter block"];
   46 [shape=box label="Enter when"];
   47 [shape=box label="Enter when branch condition "];
@@ -121,7 +121,7 @@ subgraph test_3 {
   66 [shape=box label="Exit when branch result"];
   67 [shape=box label="Exit when"];
   68 [shape=box label="Exit block"];
-  69 [shape=box label="Exit function test_3"];
+  69 [shape=box label="Exit function test_3" style="filled"];
 
   44 -> {45};
   45 -> {46};
@@ -150,8 +150,8 @@ subgraph test_3 {
   68 -> {69};
 }
 
-subgraph test_4 {
-  70 [shape=box label="Enter function test_4"];
+subgraph cluster_test_4 {
+  70 [shape=box label="Enter function test_4" style="filled"];
   71 [shape=box label="Enter block"];
   72 [shape=box label="Enter when"];
   73 [shape=box label="Enter when branch condition "];
@@ -176,7 +176,7 @@ subgraph test_4 {
   92 [shape=box label="Exit when branch result"];
   93 [shape=box label="Exit when"];
   94 [shape=box label="Exit block"];
-  95 [shape=box label="Exit function test_4"];
+  95 [shape=box label="Exit function test_4" style="filled"];
 
   70 -> {71};
   71 -> {72};
diff --git a/compiler/fir/resolve/testData/resolve/cfg/booleanOperatorsWithConsts.dot b/compiler/fir/resolve/testData/resolve/cfg/booleanOperatorsWithConsts.dot
index ffff5409948..b540e64eb20 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/booleanOperatorsWithConsts.dot
+++ b/compiler/fir/resolve/testData/resolve/cfg/booleanOperatorsWithConsts.dot
@@ -1,8 +1,8 @@
 digraph booleanOperatorsWithConsts_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph test_1 {
-  0 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  0 [shape=box label="Enter function test_1" style="filled"];
   1 [shape=box label="Enter block"];
   2 [shape=box label="Enter when"];
   3 [shape=box label="Enter when branch condition "];
@@ -23,7 +23,7 @@ subgraph test_1 {
   18 [shape=box label="Exit when branch result"];
   19 [shape=box label="Exit when"];
   20 [shape=box label="Exit block"];
-  21 [shape=box label="Exit function test_1"];
+  21 [shape=box label="Exit function test_1" style="filled"];
 
   0 -> {1};
   1 -> {2};
@@ -48,8 +48,8 @@ subgraph test_1 {
   20 -> {21};
 }
 
-subgraph test_2 {
-  22 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  22 [shape=box label="Enter function test_2" style="filled"];
   23 [shape=box label="Enter block"];
   24 [shape=box label="Enter when"];
   25 [shape=box label="Enter when branch condition "];
@@ -71,7 +71,7 @@ subgraph test_2 {
   41 [shape=box label="Exit when branch result"];
   42 [shape=box label="Exit when"];
   43 [shape=box label="Exit block"];
-  44 [shape=box label="Exit function test_2"];
+  44 [shape=box label="Exit function test_2" style="filled"];
 
   22 -> {23};
   23 -> {24};
@@ -98,8 +98,8 @@ subgraph test_2 {
   43 -> {44};
 }
 
-subgraph test_3 {
-  45 [shape=box label="Enter function test_3"];
+subgraph cluster_test_3 {
+  45 [shape=box label="Enter function test_3" style="filled"];
   46 [shape=box label="Enter block"];
   47 [shape=box label="Enter when"];
   48 [shape=box label="Enter when branch condition "];
@@ -120,7 +120,7 @@ subgraph test_3 {
   63 [shape=box label="Exit when branch result"];
   64 [shape=box label="Exit when"];
   65 [shape=box label="Exit block"];
-  66 [shape=box label="Exit function test_3"];
+  66 [shape=box label="Exit function test_3" style="filled"];
 
   45 -> {46};
   46 -> {47};
@@ -145,8 +145,8 @@ subgraph test_3 {
   65 -> {66};
 }
 
-subgraph test_4 {
-  67 [shape=box label="Enter function test_4"];
+subgraph cluster_test_4 {
+  67 [shape=box label="Enter function test_4" style="filled"];
   68 [shape=box label="Enter block"];
   69 [shape=box label="Enter when"];
   70 [shape=box label="Enter when branch condition "];
@@ -168,7 +168,7 @@ subgraph test_4 {
   86 [shape=box label="Exit when branch result"];
   87 [shape=box label="Exit when"];
   88 [shape=box label="Exit block"];
-  89 [shape=box label="Exit function test_4"];
+  89 [shape=box label="Exit function test_4" style="filled"];
 
   67 -> {68};
   68 -> {69};
@@ -195,8 +195,8 @@ subgraph test_4 {
   88 -> {89};
 }
 
-subgraph test_5 {
-  90 [shape=box label="Enter function test_5"];
+subgraph cluster_test_5 {
+  90 [shape=box label="Enter function test_5" style="filled"];
   91 [shape=box label="Enter block"];
   92 [shape=box label="Enter when"];
   93 [shape=box label="Enter when branch condition "];
@@ -217,7 +217,7 @@ subgraph test_5 {
   108 [shape=box label="Exit when branch result"];
   109 [shape=box label="Exit when"];
   110 [shape=box label="Exit block"];
-  111 [shape=box label="Exit function test_5"];
+  111 [shape=box label="Exit function test_5" style="filled"];
 
   90 -> {91};
   91 -> {92};
@@ -242,8 +242,8 @@ subgraph test_5 {
   110 -> {111};
 }
 
-subgraph test_6 {
-  112 [shape=box label="Enter function test_6"];
+subgraph cluster_test_6 {
+  112 [shape=box label="Enter function test_6" style="filled"];
   113 [shape=box label="Enter block"];
   114 [shape=box label="Enter when"];
   115 [shape=box label="Enter when branch condition "];
@@ -266,7 +266,7 @@ subgraph test_6 {
   132 [shape=box label="Exit when branch result"];
   133 [shape=box label="Exit when"];
   134 [shape=box label="Exit block"];
-  135 [shape=box label="Exit function test_6"];
+  135 [shape=box label="Exit function test_6" style="filled"];
 
   112 -> {113};
   113 -> {114};
@@ -294,8 +294,8 @@ subgraph test_6 {
   134 -> {135};
 }
 
-subgraph test_7 {
-  136 [shape=box label="Enter function test_7"];
+subgraph cluster_test_7 {
+  136 [shape=box label="Enter function test_7" style="filled"];
   137 [shape=box label="Enter block"];
   138 [shape=box label="Enter when"];
   139 [shape=box label="Enter when branch condition "];
@@ -316,7 +316,7 @@ subgraph test_7 {
   154 [shape=box label="Exit when branch result"];
   155 [shape=box label="Exit when"];
   156 [shape=box label="Exit block"];
-  157 [shape=box label="Exit function test_7"];
+  157 [shape=box label="Exit function test_7" style="filled"];
 
   136 -> {137};
   137 -> {138};
@@ -341,8 +341,8 @@ subgraph test_7 {
   156 -> {157};
 }
 
-subgraph test_8 {
-  158 [shape=box label="Enter function test_8"];
+subgraph cluster_test_8 {
+  158 [shape=box label="Enter function test_8" style="filled"];
   159 [shape=box label="Enter block"];
   160 [shape=box label="Enter when"];
   161 [shape=box label="Enter when branch condition "];
@@ -364,7 +364,7 @@ subgraph test_8 {
   177 [shape=box label="Exit when branch result"];
   178 [shape=box label="Exit when"];
   179 [shape=box label="Exit block"];
-  180 [shape=box label="Exit function test_8"];
+  180 [shape=box label="Exit function test_8" style="filled"];
 
   158 -> {159};
   159 -> {160};
diff --git a/compiler/fir/resolve/testData/resolve/cfg/complex.dot b/compiler/fir/resolve/testData/resolve/cfg/complex.dot
index b94c93f4888..5582bb27489 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/complex.dot
+++ b/compiler/fir/resolve/testData/resolve/cfg/complex.dot
@@ -1,8 +1,8 @@
 digraph complex_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph fetchPluginReleaseDate {
-  0 [shape=box label="Enter function fetchPluginReleaseDate"];
+subgraph cluster_fetchPluginReleaseDate {
+  0 [shape=box label="Enter function fetchPluginReleaseDate" style="filled"];
   1 [shape=box label="Enter block"];
   2 [shape=box label="Const: String(https://plugins.jetbrains.com/api/plugins/)"];
   3 [shape=box label="Access variable R|<local>/pluginId|"];
@@ -46,7 +46,7 @@ subgraph fetchPluginReleaseDate {
   38 [shape=box label="Access variable <Unresolved name: IOException>#"];
   39 [shape=box label="Access variable <Unresolved name: ResponseParseException>#"];
   40 [shape=box label="Exit annotation"];
-  41 [shape=box label="Exit function fetchPluginReleaseDate"];
+  41 [shape=box label="Exit function fetchPluginReleaseDate" style="filled"];
 
   0 -> {1};
   1 -> {2};
diff --git a/compiler/fir/resolve/testData/resolve/cfg/initBlock.dot b/compiler/fir/resolve/testData/resolve/cfg/initBlock.dot
index e88c7ea4110..3a4e2ace95e 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/initBlock.dot
+++ b/compiler/fir/resolve/testData/resolve/cfg/initBlock.dot
@@ -1,16 +1,16 @@
 digraph initBlock_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph <init> {
-  0 [shape=box label="Enter function <init>"];
-  1 [shape=box label="Exit function <init>"];
+subgraph cluster__init_ {
+  0 [shape=box label="Enter function <init>" style="filled"];
+  1 [shape=box label="Exit function <init>" style="filled"];
 
   0 -> {1};
 }
 
-subgraph <init> {
-  2 [shape=box label="Enter function <init>"];
-  3 [shape=box label="Exit function <init>"];
+subgraph cluster__init_ {
+  2 [shape=box label="Enter function <init>" style="filled"];
+  3 [shape=box label="Exit function <init>" style="filled"];
 
   2 -> {3};
 }
diff --git a/compiler/fir/resolve/testData/resolve/cfg/jumps.dot b/compiler/fir/resolve/testData/resolve/cfg/jumps.dot
index b48a721f457..c61546efd4e 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/jumps.dot
+++ b/compiler/fir/resolve/testData/resolve/cfg/jumps.dot
@@ -1,8 +1,8 @@
 digraph jumps_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph test_1 {
-  0 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  0 [shape=box label="Enter function test_1" style="filled"];
   1 [shape=box label="Enter block"];
   2 [shape=box label="Enter when"];
   3 [shape=box label="Enter when branch condition "];
@@ -27,7 +27,7 @@ subgraph test_1 {
   22 [shape=box label="Access variable R|<local>/y|"];
   23 [shape=box label="Function call: R|<local>/y|.R|kotlin/Int.inc|()"];
   24 [shape=box label="Exit block"];
-  25 [shape=box label="Exit function test_1"];
+  25 [shape=box label="Exit function test_1" style="filled"];
 
   0 -> {1};
   1 -> {2};
@@ -57,8 +57,8 @@ subgraph test_1 {
   24 -> {25};
 }
 
-subgraph test_2 {
-  26 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  26 [shape=box label="Enter function test_2" style="filled"];
   27 [shape=box label="Enter block"];
   28 [shape=box label="Enter when"];
   29 [shape=box label="Enter when branch condition "];
@@ -81,7 +81,7 @@ subgraph test_2 {
   46 [shape=box label="Access variable R|<local>/y|"];
   47 [shape=box label="Function call: R|<local>/y|.<Ambiguity: inc, [kotlin/inc, kotlin/inc]>#()"];
   48 [shape=box label="Exit block"];
-  49 [shape=box label="Exit function test_2"];
+  49 [shape=box label="Exit function test_2" style="filled"];
 
   26 -> {27};
   27 -> {28};
@@ -108,8 +108,8 @@ subgraph test_2 {
   48 -> {49};
 }
 
-subgraph test_3 {
-  50 [shape=box label="Enter function test_3"];
+subgraph cluster_test_3 {
+  50 [shape=box label="Enter function test_3" style="filled"];
   51 [shape=box label="Enter block"];
   52 [shape=box label="Enter while loop"];
   53 [shape=box label="Enter loop condition"];
@@ -128,7 +128,7 @@ subgraph test_3 {
   66 [shape=box label="Access variable R|<local>/x|"];
   67 [shape=box label="Function call: R|<local>/x|.R|kotlin/Int.inc|()"];
   68 [shape=box label="Exit block"];
-  69 [shape=box label="Exit function test_3"];
+  69 [shape=box label="Exit function test_3" style="filled"];
 
   50 -> {51};
   51 -> {52};
@@ -153,8 +153,8 @@ subgraph test_3 {
   68 -> {69};
 }
 
-subgraph test_4 {
-  70 [shape=box label="Enter function test_4"];
+subgraph cluster_test_4 {
+  70 [shape=box label="Enter function test_4" style="filled"];
   71 [shape=box label="Enter block"];
   72 [shape=box label="Enter do-while loop"];
   73 [shape=box label="Enter loop block"];
@@ -173,7 +173,7 @@ subgraph test_4 {
   86 [shape=box label="Access variable R|<local>/x|"];
   87 [shape=box label="Function call: R|<local>/x|.R|kotlin/Int.inc|()"];
   88 [shape=box label="Exit block"];
-  89 [shape=box label="Exit function test_4"];
+  89 [shape=box label="Exit function test_4" style="filled"];
 
   70 -> {71};
   71 -> {72};
diff --git a/compiler/fir/resolve/testData/resolve/cfg/lambdas.dot b/compiler/fir/resolve/testData/resolve/cfg/lambdas.dot
index a176169badd..721ee8e6abd 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/lambdas.dot
+++ b/compiler/fir/resolve/testData/resolve/cfg/lambdas.dot
@@ -1,12 +1,12 @@
 digraph lambdas_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph run {
-  0 [shape=box label="Enter function run"];
+subgraph cluster_run {
+  0 [shape=box label="Enter function run" style="filled"];
   1 [shape=box label="Enter block"];
   2 [shape=box label="Function call: R|<local>/block|.R|FakeOverride<kotlin/Function0.invoke: R|kotlin/Unit|>|()"];
   3 [shape=box label="Exit block"];
-  4 [shape=box label="Exit function run"];
+  4 [shape=box label="Exit function run" style="filled"];
 
   0 -> {1};
   1 -> {2};
@@ -14,8 +14,8 @@ subgraph run {
   3 -> {4};
 }
 
-subgraph test_1 {
-  5 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  5 [shape=box label="Enter function test_1" style="filled"];
   6 [shape=box label="Enter block"];
   7 [shape=box label="Enter when"];
   8 [shape=box label="Enter when branch condition "];
@@ -42,7 +42,7 @@ subgraph test_1 {
   26 [shape=box label="Exit when branch result"];
   27 [shape=box label="Exit when"];
   28 [shape=box label="Exit block"];
-  29 [shape=box label="Exit function test_1"];
+  29 [shape=box label="Exit function test_1" style="filled"];
 
   5 -> {6};
   6 -> {7};
@@ -70,13 +70,13 @@ subgraph test_1 {
   28 -> {29};
 }
 
-subgraph <anonymous> {
-  30 [shape=box label="Enter function anonymousFunction"];
+subgraph cluster__anonymous_ {
+  30 [shape=box label="Enter function anonymousFunction" style="filled"];
   31 [shape=box label="Enter block"];
   32 [shape=box label="Access variable R|<local>/x|"];
   33 [shape=box label="Function call: R|<local>/x|.<Ambiguity: inc, [kotlin/inc, kotlin/inc]>#()"];
   34 [shape=box label="Exit block"];
-  35 [shape=box label="Exit function anonymousFunction"];
+  35 [shape=box label="Exit function anonymousFunction" style="filled"];
 
   30 -> {31};
   31 -> {32};
@@ -85,8 +85,8 @@ subgraph <anonymous> {
   34 -> {35};
 }
 
-subgraph test_2 {
-  36 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  36 [shape=box label="Enter function test_2" style="filled"];
   37 [shape=box label="Enter block"];
   38 [shape=box label="Enter when"];
   39 [shape=box label="Enter when branch condition "];
@@ -104,7 +104,7 @@ subgraph test_2 {
   51 [shape=box label="Exit when branch result"];
   52 [shape=box label="Exit when"];
   53 [shape=box label="Exit block"];
-  54 [shape=box label="Exit function test_2"];
+  54 [shape=box label="Exit function test_2" style="filled"];
 
   36 -> {37};
   37 -> {38};
diff --git a/compiler/fir/resolve/testData/resolve/cfg/loops.dot b/compiler/fir/resolve/testData/resolve/cfg/loops.dot
index 2c00a6a8439..950118a6198 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/loops.dot
+++ b/compiler/fir/resolve/testData/resolve/cfg/loops.dot
@@ -1,8 +1,8 @@
 digraph loops_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph testWhile {
-  0 [shape=box label="Enter function testWhile"];
+subgraph cluster_testWhile {
+  0 [shape=box label="Enter function testWhile" style="filled"];
   1 [shape=box label="Enter block"];
   2 [shape=box label="Enter while loop"];
   3 [shape=box label="Enter loop condition"];
@@ -19,7 +19,7 @@ subgraph testWhile {
   14 [shape=box label="Access variable R|<local>/x|"];
   15 [shape=box label="Type operator: x is String"];
   16 [shape=box label="Exit block"];
-  17 [shape=box label="Exit function testWhile"];
+  17 [shape=box label="Exit function testWhile" style="filled"];
 
   0 -> {1};
   1 -> {2};
@@ -40,8 +40,8 @@ subgraph testWhile {
   16 -> {17};
 }
 
-subgraph testDoWhile {
-  18 [shape=box label="Enter function testDoWhile"];
+subgraph cluster_testDoWhile {
+  18 [shape=box label="Enter function testDoWhile" style="filled"];
   19 [shape=box label="Enter block"];
   20 [shape=box label="Enter do-while loop"];
   21 [shape=box label="Enter loop block"];
@@ -58,7 +58,7 @@ subgraph testDoWhile {
   32 [shape=box label="Access variable R|<local>/x|"];
   33 [shape=box label="Type operator: x is String"];
   34 [shape=box label="Exit block"];
-  35 [shape=box label="Exit function testDoWhile"];
+  35 [shape=box label="Exit function testDoWhile" style="filled"];
 
   18 -> {19};
   19 -> {20};
@@ -79,8 +79,8 @@ subgraph testDoWhile {
   34 -> {35};
 }
 
-subgraph testFor {
-  36 [shape=box label="Enter function testFor"];
+subgraph cluster_testFor {
+  36 [shape=box label="Enter function testFor" style="filled"];
   37 [shape=box label="Enter block"];
   38 [shape=box label="Const: Int(0)"];
   39 [shape=box label="Const: Int(5)"];
@@ -108,7 +108,7 @@ subgraph testFor {
   61 [shape=box label="Access variable R|<local>/x|"];
   62 [shape=box label="Type operator: x is String"];
   63 [shape=box label="Exit block"];
-  64 [shape=box label="Exit function testFor"];
+  64 [shape=box label="Exit function testFor" style="filled"];
 
   36 -> {37};
   37 -> {38};
@@ -140,8 +140,8 @@ subgraph testFor {
   63 -> {64};
 }
 
-subgraph testWhileTrue {
-  65 [shape=box label="Enter function testWhileTrue"];
+subgraph cluster_testWhileTrue {
+  65 [shape=box label="Enter function testWhileTrue" style="filled"];
   66 [shape=box label="Enter block"];
   67 [shape=box label="Enter while loop"];
   68 [shape=box label="Enter loop condition"];
@@ -156,7 +156,7 @@ subgraph testWhileTrue {
   77 [shape=box label="Exit whileloop[DEAD]"];
   78 [shape=box label="Const: Int(1)[DEAD]"];
   79 [shape=box label="Exit block[DEAD]"];
-  80 [shape=box label="Exit function testWhileTrue[DEAD]"];
+  80 [shape=box label="Exit function testWhileTrue[DEAD]" style="filled"];
 
   65 -> {66};
   66 -> {67};
@@ -176,8 +176,8 @@ subgraph testWhileTrue {
   79 -> {80} [style=dotted];
 }
 
-subgraph testWhileTrueWithBreak {
-  81 [shape=box label="Enter function testWhileTrueWithBreak"];
+subgraph cluster_testWhileTrueWithBreak {
+  81 [shape=box label="Enter function testWhileTrueWithBreak" style="filled"];
   82 [shape=box label="Enter block"];
   83 [shape=box label="Enter while loop"];
   84 [shape=box label="Enter loop condition"];
@@ -206,7 +206,7 @@ subgraph testWhileTrueWithBreak {
   107 [shape=box label="Exit whileloop"];
   108 [shape=box label="Const: Int(1)"];
   109 [shape=box label="Exit block"];
-  110 [shape=box label="Exit function testWhileTrueWithBreak"];
+  110 [shape=box label="Exit function testWhileTrueWithBreak" style="filled"];
 
   81 -> {82};
   82 -> {83};
@@ -241,8 +241,8 @@ subgraph testWhileTrueWithBreak {
   109 -> {110};
 }
 
-subgraph testWhileFalse {
-  111 [shape=box label="Enter function testWhileFalse"];
+subgraph cluster_testWhileFalse {
+  111 [shape=box label="Enter function testWhileFalse" style="filled"];
   112 [shape=box label="Enter block"];
   113 [shape=box label="Enter while loop"];
   114 [shape=box label="Enter loop condition"];
@@ -257,7 +257,7 @@ subgraph testWhileFalse {
   123 [shape=box label="Exit whileloop"];
   124 [shape=box label="Const: Int(1)"];
   125 [shape=box label="Exit block"];
-  126 [shape=box label="Exit function testWhileFalse"];
+  126 [shape=box label="Exit function testWhileFalse" style="filled"];
 
   111 -> {112};
   112 -> {113};
@@ -277,8 +277,8 @@ subgraph testWhileFalse {
   125 -> {126};
 }
 
-subgraph testDoWhileTrue {
-  127 [shape=box label="Enter function testDoWhileTrue"];
+subgraph cluster_testDoWhileTrue {
+  127 [shape=box label="Enter function testDoWhileTrue" style="filled"];
   128 [shape=box label="Enter block"];
   129 [shape=box label="Enter do-while loop"];
   130 [shape=box label="Enter loop block"];
@@ -293,7 +293,7 @@ subgraph testDoWhileTrue {
   139 [shape=box label="Exit do-whileloop[DEAD]"];
   140 [shape=box label="Const: Int(1)[DEAD]"];
   141 [shape=box label="Exit block[DEAD]"];
-  142 [shape=box label="Exit function testDoWhileTrue[DEAD]"];
+  142 [shape=box label="Exit function testDoWhileTrue[DEAD]" style="filled"];
 
   127 -> {128};
   128 -> {129};
@@ -313,8 +313,8 @@ subgraph testDoWhileTrue {
   141 -> {142} [style=dotted];
 }
 
-subgraph testDoWhileTrueWithBreak {
-  143 [shape=box label="Enter function testDoWhileTrueWithBreak"];
+subgraph cluster_testDoWhileTrueWithBreak {
+  143 [shape=box label="Enter function testDoWhileTrueWithBreak" style="filled"];
   144 [shape=box label="Enter block"];
   145 [shape=box label="Enter do-while loop"];
   146 [shape=box label="Enter loop block"];
@@ -343,7 +343,7 @@ subgraph testDoWhileTrueWithBreak {
   169 [shape=box label="Exit do-whileloop"];
   170 [shape=box label="Const: Int(1)"];
   171 [shape=box label="Exit block"];
-  172 [shape=box label="Exit function testDoWhileTrueWithBreak"];
+  172 [shape=box label="Exit function testDoWhileTrueWithBreak" style="filled"];
 
   143 -> {144};
   144 -> {145};
@@ -378,8 +378,8 @@ subgraph testDoWhileTrueWithBreak {
   171 -> {172};
 }
 
-subgraph testDoWhileFalse {
-  173 [shape=box label="Enter function testDoWhileFalse"];
+subgraph cluster_testDoWhileFalse {
+  173 [shape=box label="Enter function testDoWhileFalse" style="filled"];
   174 [shape=box label="Enter block"];
   175 [shape=box label="Enter do-while loop"];
   176 [shape=box label="Enter loop block"];
@@ -393,7 +393,7 @@ subgraph testDoWhileFalse {
   184 [shape=box label="Exit do-whileloop"];
   185 [shape=box label="Const: Int(1)"];
   186 [shape=box label="Exit block"];
-  187 [shape=box label="Exit function testDoWhileFalse"];
+  187 [shape=box label="Exit function testDoWhileFalse" style="filled"];
   188 [shape=box label="Stub[DEAD]"];
 
   173 -> {174};
diff --git a/compiler/fir/resolve/testData/resolve/cfg/propertiesAndInitBlocks.dot b/compiler/fir/resolve/testData/resolve/cfg/propertiesAndInitBlocks.dot
index 3df4ade76a9..43237216bc3 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/propertiesAndInitBlocks.dot
+++ b/compiler/fir/resolve/testData/resolve/cfg/propertiesAndInitBlocks.dot
@@ -1,12 +1,12 @@
 digraph propertiesAndInitBlocks_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph run {
-  0 [shape=box label="Enter function run"];
+subgraph cluster_run {
+  0 [shape=box label="Enter function run" style="filled"];
   1 [shape=box label="Enter block"];
   2 [shape=box label="Function call: R|<local>/block|.R|FakeOverride<kotlin/Function0.invoke: R|kotlin/Unit|>|()"];
   3 [shape=box label="Exit block"];
-  4 [shape=box label="Exit function run"];
+  4 [shape=box label="Exit function run" style="filled"];
 
   0 -> {1};
   1 -> {2};
@@ -14,23 +14,23 @@ subgraph run {
   3 -> {4};
 }
 
-subgraph val_x1 {
-  5 [shape=box label="Enter property"];
+subgraph cluster_val_x1 {
+  5 [shape=box label="Enter property" style="filled"];
   6 [shape=box label="Const: Int(1)"];
-  7 [shape=box label="Exit property"];
+  7 [shape=box label="Exit property" style="filled"];
 
   5 -> {6};
   6 -> {7};
 }
 
-subgraph <getter> {
-  8 [shape=box label="Enter function getter"];
+subgraph cluster__getter_ {
+  8 [shape=box label="Enter function getter" style="filled"];
   9 [shape=box label="Enter block"];
   10 [shape=box label="Const: Int(1)"];
   11 [shape=box label="Jump: ^ Int(1)"];
   12 [shape=box label="Stub[DEAD]"];
   13 [shape=box label="Exit block[DEAD]"];
-  14 [shape=box label="Exit function getter[DEAD]"];
+  14 [shape=box label="Exit function getter[DEAD]" style="filled"];
 
   8 -> {9};
   9 -> {10};
@@ -40,13 +40,13 @@ subgraph <getter> {
   13 -> {14} [style=dotted];
 }
 
-subgraph <setter> {
-  15 [shape=box label="Enter function setter"];
+subgraph cluster__setter_ {
+  15 [shape=box label="Enter function setter" style="filled"];
   16 [shape=box label="Enter block"];
   17 [shape=box label="Const: Int(1)"];
   18 [shape=box label="Assignmenet: F|/x2|"];
   19 [shape=box label="Exit block"];
-  20 [shape=box label="Exit function setter"];
+  20 [shape=box label="Exit function setter" style="filled"];
 
   15 -> {16};
   16 -> {17};
@@ -55,17 +55,17 @@ subgraph <setter> {
   19 -> {20};
 }
 
-subgraph val_x2 {
-  21 [shape=box label="Enter property"];
+subgraph cluster_val_x2 {
+  21 [shape=box label="Enter property" style="filled"];
   22 [shape=box label="Const: Int(1)"];
-  23 [shape=box label="Exit property"];
+  23 [shape=box label="Exit property" style="filled"];
 
   21 -> {22};
   22 -> {23};
 }
 
-subgraph foo {
-  24 [shape=box label="Enter function foo"];
+subgraph cluster_foo {
+  24 [shape=box label="Enter function foo" style="filled"];
   25 [shape=box label="Enter block"];
   26 [shape=box label="Const: Int(1)"];
   27 [shape=box label="Const: Int(1)"];
@@ -75,7 +75,7 @@ subgraph foo {
   31 [shape=box label="Throw: throw <Ambiguity: Exception, [java/lang/Exception.Exception, java/lang/Exception.Exception]>#()"];
   32 [shape=box label="Stub[DEAD]"];
   33 [shape=box label="Exit block[DEAD]"];
-  34 [shape=box label="Exit function foo[DEAD]"];
+  34 [shape=box label="Exit function foo[DEAD]" style="filled"];
 
   24 -> {25};
   25 -> {26};
@@ -89,14 +89,14 @@ subgraph foo {
   33 -> {34} [style=dotted];
 }
 
-subgraph <init> {
-  35 [shape=box label="Enter function <init>"];
-  36 [shape=box label="Exit function <init>"];
+subgraph cluster__init_ {
+  35 [shape=box label="Enter function <init>" style="filled"];
+  36 [shape=box label="Exit function <init>" style="filled"];
 
   35 -> {36};
 }
 
-subgraph <getter> {
+subgraph cluster__getter_ {
   37 [shape=box label="Enter init block"];
   38 [shape=box label="Enter block"];
   39 [shape=box label="Function call: <Ambiguity: Exception, [java/lang/Exception.Exception, java/lang/Exception.Exception]>#()"];
@@ -104,10 +104,10 @@ subgraph <getter> {
   41 [shape=box label="Stub[DEAD]"];
   42 [shape=box label="Exit block[DEAD]"];
   43 [shape=box label="Exit init block[DEAD]"];
-  44 [shape=box label="Enter function getter"];
+  44 [shape=box label="Enter function getter" style="filled"];
   45 [shape=box label="Enter block"];
   46 [shape=box label="Exit block"];
-  47 [shape=box label="Exit function getter"];
+  47 [shape=box label="Exit function getter" style="filled"];
 
   37 -> {38};
   38 -> {39};
@@ -120,14 +120,14 @@ subgraph <getter> {
   46 -> {47};
 }
 
-subgraph <init> {
-  48 [shape=box label="Enter function <init>"];
-  49 [shape=box label="Exit function <init>"];
+subgraph cluster__init_ {
+  48 [shape=box label="Enter function <init>" style="filled"];
+  49 [shape=box label="Exit function <init>" style="filled"];
 
   48 -> {49};
 }
 
-subgraph val_x3 {
+subgraph cluster_val_x3 {
   50 [shape=box label="Enter init block"];
   51 [shape=box label="Enter block"];
   52 [shape=box label="Function call: <Ambiguity: Exception, [java/lang/Exception.Exception, java/lang/Exception.Exception]>#()"];
@@ -136,7 +136,7 @@ subgraph val_x3 {
   55 [shape=box label="Const: Int(1)[DEAD]"];
   56 [shape=box label="Exit block[DEAD]"];
   57 [shape=box label="Exit init block[DEAD]"];
-  58 [shape=box label="Enter property"];
+  58 [shape=box label="Enter property" style="filled"];
   59 [shape=box label="Enter function anonymousFunction"];
   60 [shape=box label="Enter block"];
   61 [shape=box label="Function call: <Ambiguity: Exception, [java/lang/Exception.Exception, java/lang/Exception.Exception]>#()"];
@@ -165,7 +165,7 @@ subgraph val_x3 {
     throw <Ambiguity: Exception, [java/lang/Exception.Exception, java/lang/Exception.Exception]>#()
 }
 )[DEAD]"];
-  67 [shape=box label="Exit property[DEAD]"];
+  67 [shape=box label="Exit property[DEAD]" style="filled"];
 
   50 -> {51};
   51 -> {52};
@@ -185,8 +185,8 @@ subgraph val_x3 {
   66 -> {67} [style=dotted];
 }
 
-subgraph val_x4 {
-  68 [shape=box label="Enter property"];
+subgraph cluster_val_x4 {
+  68 [shape=box label="Enter property" style="filled"];
   69 [shape=box label="Try expression enter"];
   70 [shape=box label="Try main block enter"];
   71 [shape=box label="Enter block"];
@@ -204,7 +204,7 @@ subgraph val_x4 {
   83 [shape=box label="Exit block"];
   84 [shape=box label="Catch exit"];
   85 [shape=box label="Try expression exit"];
-  86 [shape=box label="Exit property"];
+  86 [shape=box label="Exit property" style="filled"];
 
   68 -> {69};
   69 -> {70};
diff --git a/compiler/fir/resolve/testData/resolve/cfg/simple.dot b/compiler/fir/resolve/testData/resolve/cfg/simple.dot
index 089d912a8db..7669cb0297c 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/simple.dot
+++ b/compiler/fir/resolve/testData/resolve/cfg/simple.dot
@@ -1,19 +1,19 @@
 digraph simple_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph foo {
-  0 [shape=box label="Enter function foo"];
+subgraph cluster_foo {
+  0 [shape=box label="Enter function foo" style="filled"];
   1 [shape=box label="Enter block"];
   2 [shape=box label="Exit block"];
-  3 [shape=box label="Exit function foo"];
+  3 [shape=box label="Exit function foo" style="filled"];
 
   0 -> {1};
   1 -> {2};
   2 -> {3};
 }
 
-subgraph test {
-  4 [shape=box label="Enter function test"];
+subgraph cluster_test {
+  4 [shape=box label="Enter function test" style="filled"];
   5 [shape=box label="Enter block"];
   6 [shape=box label="Const: Int(1)"];
   7 [shape=box label="Variable declaration: lval x: R|kotlin/Int|"];
@@ -23,7 +23,7 @@ subgraph test {
   11 [shape=box label="Variable declaration: lval y: R|kotlin/Int|"];
   12 [shape=box label="Function call: R|/foo|()"];
   13 [shape=box label="Exit block"];
-  14 [shape=box label="Exit function test"];
+  14 [shape=box label="Exit function test" style="filled"];
 
   4 -> {5};
   5 -> {6};
diff --git a/compiler/fir/resolve/testData/resolve/cfg/tryCatch.dot b/compiler/fir/resolve/testData/resolve/cfg/tryCatch.dot
index f218dc83b25..a0608584f5d 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/tryCatch.dot
+++ b/compiler/fir/resolve/testData/resolve/cfg/tryCatch.dot
@@ -1,8 +1,8 @@
 digraph tryCatch_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph test_1 {
-  0 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  0 [shape=box label="Enter function test_1" style="filled"];
   1 [shape=box label="Enter block"];
   2 [shape=box label="Try expression enter"];
   3 [shape=box label="Try main block enter"];
@@ -25,7 +25,7 @@ subgraph test_1 {
   20 [shape=box label="Catch exit"];
   21 [shape=box label="Try expression exit"];
   22 [shape=box label="Exit block"];
-  23 [shape=box label="Exit function test_1"];
+  23 [shape=box label="Exit function test_1" style="filled"];
 
   0 -> {1};
   1 -> {2};
@@ -52,8 +52,8 @@ subgraph test_1 {
   22 -> {23};
 }
 
-subgraph test_2 {
-  24 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  24 [shape=box label="Enter function test_2" style="filled"];
   25 [shape=box label="Enter block"];
   26 [shape=box label="Try expression enter"];
   27 [shape=box label="Try main block enter"];
@@ -69,7 +69,7 @@ subgraph test_2 {
   37 [shape=box label="Try expression exit"];
   38 [shape=box label="Variable declaration: lval x: R|kotlin/Int|"];
   39 [shape=box label="Exit block"];
-  40 [shape=box label="Exit function test_2"];
+  40 [shape=box label="Exit function test_2" style="filled"];
 
   24 -> {25};
   25 -> {26};
@@ -89,8 +89,8 @@ subgraph test_2 {
   39 -> {40};
 }
 
-subgraph test_3 {
-  41 [shape=box label="Enter function test_3"];
+subgraph cluster_test_3 {
+  41 [shape=box label="Enter function test_3" style="filled"];
   42 [shape=box label="Enter block"];
   43 [shape=box label="Enter while loop"];
   44 [shape=box label="Enter loop condition"];
@@ -158,7 +158,7 @@ subgraph test_3 {
   106 [shape=box label="Const: Int(3)"];
   107 [shape=box label="Variable declaration: lval z: R|kotlin/Int|"];
   108 [shape=box label="Exit block"];
-  109 [shape=box label="Exit function test_3"];
+  109 [shape=box label="Exit function test_3" style="filled"];
 
   41 -> {42};
   42 -> {43};
diff --git a/compiler/fir/resolve/testData/resolve/cfg/when.dot b/compiler/fir/resolve/testData/resolve/cfg/when.dot
index af095017b70..2ae0e1b3039 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/when.dot
+++ b/compiler/fir/resolve/testData/resolve/cfg/when.dot
@@ -1,8 +1,8 @@
 digraph when_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph test_1 {
-  0 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  0 [shape=box label="Enter function test_1" style="filled"];
   1 [shape=box label="Enter block"];
   2 [shape=box label="Enter when"];
   3 [shape=box label="Enter when branch condition "];
@@ -46,7 +46,7 @@ subgraph test_1 {
   41 [shape=box label="Exit when"];
   42 [shape=box label="Variable declaration: lval y: R|kotlin/Int|"];
   43 [shape=box label="Exit block"];
-  44 [shape=box label="Exit function test_1"];
+  44 [shape=box label="Exit function test_1" style="filled"];
 
   0 -> {1};
   1 -> {2};
@@ -95,8 +95,8 @@ subgraph test_1 {
   43 -> {44};
 }
 
-subgraph test_2 {
-  45 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  45 [shape=box label="Enter function test_2" style="filled"];
   46 [shape=box label="Enter block"];
   47 [shape=box label="Enter when"];
   48 [shape=box label="Enter when branch condition "];
@@ -120,7 +120,7 @@ subgraph test_2 {
   66 [shape=box label="Exit when branch result"];
   67 [shape=box label="Exit when"];
   68 [shape=box label="Exit block"];
-  69 [shape=box label="Exit function test_2"];
+  69 [shape=box label="Exit function test_2" style="filled"];
 
   45 -> {46};
   46 -> {47};
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/booleanOperators.dot b/compiler/fir/resolve/testData/resolve/smartcasts/booleanOperators.dot
index 1561d1e04ba..76be6d59dc6 100644
--- a/compiler/fir/resolve/testData/resolve/smartcasts/booleanOperators.dot
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/booleanOperators.dot
@@ -1,36 +1,36 @@
 digraph booleanOperators_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph foo {
-  0 [shape=box label="Enter function foo"];
-  1 [shape=box label="Exit function foo"];
+subgraph cluster_foo {
+  0 [shape=box label="Enter function foo" style="filled"];
+  1 [shape=box label="Exit function foo" style="filled"];
 
   0 -> {1};
 }
 
-subgraph bool {
-  2 [shape=box label="Enter function bool"];
-  3 [shape=box label="Exit function bool"];
+subgraph cluster_bool {
+  2 [shape=box label="Enter function bool" style="filled"];
+  3 [shape=box label="Exit function bool" style="filled"];
 
   2 -> {3};
 }
 
-subgraph bar {
-  4 [shape=box label="Enter function bar"];
-  5 [shape=box label="Exit function bar"];
+subgraph cluster_bar {
+  4 [shape=box label="Enter function bar" style="filled"];
+  5 [shape=box label="Exit function bar" style="filled"];
 
   4 -> {5};
 }
 
-subgraph baz {
-  6 [shape=box label="Enter function baz"];
-  7 [shape=box label="Exit function baz"];
+subgraph cluster_baz {
+  6 [shape=box label="Enter function baz" style="filled"];
+  7 [shape=box label="Exit function baz" style="filled"];
 
   6 -> {7};
 }
 
-subgraph test_1 {
-  8 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  8 [shape=box label="Enter function test_1" style="filled"];
   9 [shape=box label="Enter block"];
   10 [shape=box label="Enter when"];
   11 [shape=box label="Enter when branch condition "];
@@ -58,7 +58,7 @@ subgraph test_1 {
   33 [shape=box label="Exit when branch result"];
   34 [shape=box label="Exit when"];
   35 [shape=box label="Exit block"];
-  36 [shape=box label="Exit function test_1"];
+  36 [shape=box label="Exit function test_1" style="filled"];
 
   8 -> {9};
   9 -> {10};
@@ -90,8 +90,8 @@ subgraph test_1 {
   35 -> {36};
 }
 
-subgraph test_2 {
-  37 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  37 [shape=box label="Enter function test_2" style="filled"];
   38 [shape=box label="Enter block"];
   39 [shape=box label="Enter when"];
   40 [shape=box label="Enter when branch condition "];
@@ -119,7 +119,7 @@ subgraph test_2 {
   62 [shape=box label="Exit when branch result"];
   63 [shape=box label="Exit when"];
   64 [shape=box label="Exit block"];
-  65 [shape=box label="Exit function test_2"];
+  65 [shape=box label="Exit function test_2" style="filled"];
 
   37 -> {38};
   38 -> {39};
@@ -151,8 +151,8 @@ subgraph test_2 {
   64 -> {65};
 }
 
-subgraph test_3 {
-  66 [shape=box label="Enter function test_3"];
+subgraph cluster_test_3 {
+  66 [shape=box label="Enter function test_3" style="filled"];
   67 [shape=box label="Enter block"];
   68 [shape=box label="Enter when"];
   69 [shape=box label="Enter when branch condition "];
@@ -172,7 +172,7 @@ subgraph test_3 {
   83 [shape=box label="Exit when branch result"];
   84 [shape=box label="Exit when"];
   85 [shape=box label="Exit block"];
-  86 [shape=box label="Exit function test_3"];
+  86 [shape=box label="Exit function test_3" style="filled"];
 
   66 -> {67};
   67 -> {68};
@@ -196,8 +196,8 @@ subgraph test_3 {
   85 -> {86};
 }
 
-subgraph test_4 {
-  87 [shape=box label="Enter function test_4"];
+subgraph cluster_test_4 {
+  87 [shape=box label="Enter function test_4" style="filled"];
   88 [shape=box label="Enter block"];
   89 [shape=box label="Enter when"];
   90 [shape=box label="Enter when branch condition "];
@@ -225,7 +225,7 @@ subgraph test_4 {
   112 [shape=box label="Access variable R|<local>/x|"];
   113 [shape=box label="Access variable <Unresolved name: length>#"];
   114 [shape=box label="Exit block"];
-  115 [shape=box label="Exit function test_4"];
+  115 [shape=box label="Exit function test_4" style="filled"];
 
   87 -> {88};
   88 -> {89};
@@ -257,8 +257,8 @@ subgraph test_4 {
   114 -> {115};
 }
 
-subgraph test_5 {
-  116 [shape=box label="Enter function test_5"];
+subgraph cluster_test_5 {
+  116 [shape=box label="Enter function test_5" style="filled"];
   117 [shape=box label="Enter block"];
   118 [shape=box label="Enter when"];
   119 [shape=box label="Enter when branch condition "];
@@ -282,7 +282,7 @@ subgraph test_5 {
   137 [shape=box label="Exit when branch result"];
   138 [shape=box label="Exit when"];
   139 [shape=box label="Exit block"];
-  140 [shape=box label="Exit function test_5"];
+  140 [shape=box label="Exit function test_5" style="filled"];
 
   116 -> {117};
   117 -> {118};
@@ -310,8 +310,8 @@ subgraph test_5 {
   139 -> {140};
 }
 
-subgraph test_6 {
-  141 [shape=box label="Enter function test_6"];
+subgraph cluster_test_6 {
+  141 [shape=box label="Enter function test_6" style="filled"];
   142 [shape=box label="Enter block"];
   143 [shape=box label="Enter when"];
   144 [shape=box label="Enter when branch condition "];
@@ -336,7 +336,7 @@ subgraph test_6 {
   163 [shape=box label="Exit when branch result"];
   164 [shape=box label="Exit when"];
   165 [shape=box label="Exit block"];
-  166 [shape=box label="Exit function test_6"];
+  166 [shape=box label="Exit function test_6" style="filled"];
 
   141 -> {142};
   142 -> {143};
@@ -366,8 +366,8 @@ subgraph test_6 {
   165 -> {166};
 }
 
-subgraph test_7 {
-  167 [shape=box label="Enter function test_7"];
+subgraph cluster_test_7 {
+  167 [shape=box label="Enter function test_7" style="filled"];
   168 [shape=box label="Enter block"];
   169 [shape=box label="Enter when"];
   170 [shape=box label="Enter when branch condition "];
@@ -391,7 +391,7 @@ subgraph test_7 {
   188 [shape=box label="Exit when branch result"];
   189 [shape=box label="Exit when"];
   190 [shape=box label="Exit block"];
-  191 [shape=box label="Exit function test_7"];
+  191 [shape=box label="Exit function test_7" style="filled"];
 
   167 -> {168};
   168 -> {169};
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/boundSmartcasts.dot b/compiler/fir/resolve/testData/resolve/smartcasts/boundSmartcasts.dot
index 19802381db6..b95dfb05e9e 100644
--- a/compiler/fir/resolve/testData/resolve/smartcasts/boundSmartcasts.dot
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/boundSmartcasts.dot
@@ -1,22 +1,22 @@
 digraph boundSmartcasts_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph foo {
-  0 [shape=box label="Enter function foo"];
-  1 [shape=box label="Exit function foo"];
+subgraph cluster_foo {
+  0 [shape=box label="Enter function foo" style="filled"];
+  1 [shape=box label="Exit function foo" style="filled"];
 
   0 -> {1};
 }
 
-subgraph bar {
-  2 [shape=box label="Enter function bar"];
-  3 [shape=box label="Exit function bar"];
+subgraph cluster_bar {
+  2 [shape=box label="Enter function bar" style="filled"];
+  3 [shape=box label="Exit function bar" style="filled"];
 
   2 -> {3};
 }
 
-subgraph test_1 {
-  4 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  4 [shape=box label="Enter function test_1" style="filled"];
   5 [shape=box label="Enter block"];
   6 [shape=box label="Access variable R|<local>/x|"];
   7 [shape=box label="Variable declaration: lval y: R|kotlin/Any|"];
@@ -39,7 +39,7 @@ subgraph test_1 {
   24 [shape=box label="Exit when branch result"];
   25 [shape=box label="Exit when"];
   26 [shape=box label="Exit block"];
-  27 [shape=box label="Exit function test_1"];
+  27 [shape=box label="Exit function test_1" style="filled"];
 
   4 -> {5};
   5 -> {6};
@@ -66,8 +66,8 @@ subgraph test_1 {
   26 -> {27};
 }
 
-subgraph test_2 {
-  28 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  28 [shape=box label="Enter function test_2" style="filled"];
   29 [shape=box label="Enter block"];
   30 [shape=box label="Access variable R|<local>/x|"];
   31 [shape=box label="Variable declaration: lval y: R|kotlin/Any|"];
@@ -90,7 +90,7 @@ subgraph test_2 {
   48 [shape=box label="Exit when branch result"];
   49 [shape=box label="Exit when"];
   50 [shape=box label="Exit block"];
-  51 [shape=box label="Exit function test_2"];
+  51 [shape=box label="Exit function test_2" style="filled"];
 
   28 -> {29};
   29 -> {30};
@@ -117,8 +117,8 @@ subgraph test_2 {
   50 -> {51};
 }
 
-subgraph test_3 {
-  52 [shape=box label="Enter function test_3"];
+subgraph cluster_test_3 {
+  52 [shape=box label="Enter function test_3" style="filled"];
   53 [shape=box label="Enter block"];
   54 [shape=box label="Access variable R|<local>/x|"];
   55 [shape=box label="Variable declaration: lvar z: R|kotlin/Any|"];
@@ -157,7 +157,7 @@ subgraph test_3 {
   88 [shape=box label="Exit when branch result"];
   89 [shape=box label="Exit when"];
   90 [shape=box label="Exit block"];
-  91 [shape=box label="Exit function test_3"];
+  91 [shape=box label="Exit function test_3" style="filled"];
 
   52 -> {53};
   53 -> {54};
@@ -200,8 +200,8 @@ subgraph test_3 {
   90 -> {91};
 }
 
-subgraph test_4 {
-  92 [shape=box label="Enter function test_4"];
+subgraph cluster_test_4 {
+  92 [shape=box label="Enter function test_4" style="filled"];
   93 [shape=box label="Enter block"];
   94 [shape=box label="Const: Int(1)"];
   95 [shape=box label="Variable declaration: lvar x: R|kotlin/Any|"];
@@ -232,7 +232,7 @@ subgraph test_4 {
   120 [shape=box label="Exit when branch result"];
   121 [shape=box label="Exit when"];
   122 [shape=box label="Exit block"];
-  123 [shape=box label="Exit function test_4"];
+  123 [shape=box label="Exit function test_4" style="filled"];
 
   92 -> {93};
   93 -> {94};
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/casts.dot b/compiler/fir/resolve/testData/resolve/smartcasts/casts.dot
index 72fd19f82f0..e7c37292711 100644
--- a/compiler/fir/resolve/testData/resolve/smartcasts/casts.dot
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/casts.dot
@@ -1,15 +1,15 @@
 digraph casts_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph test_1 {
-  0 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  0 [shape=box label="Enter function test_1" style="filled"];
   1 [shape=box label="Enter block"];
   2 [shape=box label="Access variable R|<local>/x|"];
   3 [shape=box label="Type operator: x as String"];
   4 [shape=box label="Access variable R|<local>/x|"];
   5 [shape=box label="Access variable R|kotlin/String.length|"];
   6 [shape=box label="Exit block"];
-  7 [shape=box label="Exit function test_1"];
+  7 [shape=box label="Exit function test_1" style="filled"];
 
   0 -> {1};
   1 -> {2};
@@ -20,8 +20,8 @@ subgraph test_1 {
   6 -> {7};
 }
 
-subgraph test_2 {
-  8 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  8 [shape=box label="Enter function test_2" style="filled"];
   9 [shape=box label="Enter block"];
   10 [shape=box label="Enter when"];
   11 [shape=box label="Enter when branch condition "];
@@ -42,7 +42,7 @@ subgraph test_2 {
   26 [shape=box label="Access variable R|<local>/x|"];
   27 [shape=box label="Function call: R|<local>/x|.R|kotlin/Boolean.not|()"];
   28 [shape=box label="Exit block"];
-  29 [shape=box label="Exit function test_2"];
+  29 [shape=box label="Exit function test_2" style="filled"];
 
   8 -> {9};
   9 -> {10};
@@ -67,8 +67,8 @@ subgraph test_2 {
   28 -> {29};
 }
 
-subgraph test_3 {
-  30 [shape=box label="Enter function test_3"];
+subgraph cluster_test_3 {
+  30 [shape=box label="Enter function test_3" style="filled"];
   31 [shape=box label="Enter block"];
   32 [shape=box label="Enter when"];
   33 [shape=box label="Enter when branch condition "];
@@ -139,7 +139,7 @@ subgraph test_3 {
   98 [shape=box label="Access variable R|<local>/x|"];
   99 [shape=box label="Function call: R|<local>/x|.<Unresolved name: not>#()"];
   100 [shape=box label="Exit block"];
-  101 [shape=box label="Exit function test_3"];
+  101 [shape=box label="Exit function test_3" style="filled"];
 
   30 -> {31};
   31 -> {32};
@@ -214,8 +214,8 @@ subgraph test_3 {
   100 -> {101};
 }
 
-subgraph test_4 {
-  102 [shape=box label="Enter function test_4"];
+subgraph cluster_test_4 {
+  102 [shape=box label="Enter function test_4" style="filled"];
   103 [shape=box label="Enter block"];
   104 [shape=box label="Enter when"];
   105 [shape=box label="Enter when branch condition "];
@@ -262,7 +262,7 @@ subgraph test_4 {
   146 [shape=box label="Access variable R|<local>/b|"];
   147 [shape=box label="Function call: R|<local>/b|.<Unresolved name: not>#()"];
   148 [shape=box label="Exit block"];
-  149 [shape=box label="Exit function test_4"];
+  149 [shape=box label="Exit function test_4" style="filled"];
 
   102 -> {103};
   103 -> {104};
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/elvis.dot b/compiler/fir/resolve/testData/resolve/smartcasts/elvis.dot
index 7ce69a7bb45..4774965e069 100644
--- a/compiler/fir/resolve/testData/resolve/smartcasts/elvis.dot
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/elvis.dot
@@ -1,22 +1,22 @@
 digraph elvis_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph foo {
-  0 [shape=box label="Enter function foo"];
-  1 [shape=box label="Exit function foo"];
+subgraph cluster_foo {
+  0 [shape=box label="Enter function foo" style="filled"];
+  1 [shape=box label="Exit function foo" style="filled"];
 
   0 -> {1};
 }
 
-subgraph val_b {
-  2 [shape=box label="Enter property"];
-  3 [shape=box label="Exit property"];
+subgraph cluster_val_b {
+  2 [shape=box label="Enter property" style="filled"];
+  3 [shape=box label="Exit property" style="filled"];
 
   2 -> {3};
 }
 
-subgraph test_1 {
-  4 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  4 [shape=box label="Enter function test_1" style="filled"];
   5 [shape=box label="Enter block"];
   6 [shape=box label="Enter when"];
   7 [shape=box label="Enter when branch condition "];
@@ -53,7 +53,7 @@ subgraph test_1 {
   38 [shape=box label="Exit when branch result"];
   39 [shape=box label="Exit when"];
   40 [shape=box label="Exit block"];
-  41 [shape=box label="Exit function test_1"];
+  41 [shape=box label="Exit function test_1" style="filled"];
 
   4 -> {5};
   5 -> {6};
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.dot b/compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.dot
index c1d2f007071..5e3aeed17dc 100644
--- a/compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.dot
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.dot
@@ -1,15 +1,15 @@
 digraph endlessLoops_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph foo {
-  0 [shape=box label="Enter function foo"];
-  1 [shape=box label="Exit function foo"];
+subgraph cluster_foo {
+  0 [shape=box label="Enter function foo" style="filled"];
+  1 [shape=box label="Exit function foo" style="filled"];
 
   0 -> {1};
 }
 
-subgraph test_1 {
-  2 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  2 [shape=box label="Enter function test_1" style="filled"];
   3 [shape=box label="Enter block"];
   4 [shape=box label="Enter while loop"];
   5 [shape=box label="Enter loop condition"];
@@ -41,7 +41,7 @@ subgraph test_1 {
   31 [shape=box label="Access variable R|<local>/x|"];
   32 [shape=box label="Function call: R|<local>/x|.R|/A.foo|()"];
   33 [shape=box label="Exit block"];
-  34 [shape=box label="Exit function test_1"];
+  34 [shape=box label="Exit function test_1" style="filled"];
 
   2 -> {3};
   3 -> {4};
@@ -79,8 +79,8 @@ subgraph test_1 {
   33 -> {34};
 }
 
-subgraph test_2 {
-  35 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  35 [shape=box label="Enter function test_2" style="filled"];
   36 [shape=box label="Enter block"];
   37 [shape=box label="Enter while loop"];
   38 [shape=box label="Enter loop condition"];
@@ -112,7 +112,7 @@ subgraph test_2 {
   64 [shape=box label="Access variable R|<local>/x|"];
   65 [shape=box label="Function call: R|<local>/x|.R|/A.foo|()"];
   66 [shape=box label="Exit block"];
-  67 [shape=box label="Exit function test_2"];
+  67 [shape=box label="Exit function test_2" style="filled"];
 
   35 -> {36};
   36 -> {37};
@@ -150,8 +150,8 @@ subgraph test_2 {
   66 -> {67};
 }
 
-subgraph test_3 {
-  68 [shape=box label="Enter function test_3"];
+subgraph cluster_test_3 {
+  68 [shape=box label="Enter function test_3" style="filled"];
   69 [shape=box label="Enter block"];
   70 [shape=box label="Enter while loop"];
   71 [shape=box label="Enter loop condition"];
@@ -198,7 +198,7 @@ subgraph test_3 {
   112 [shape=box label="Access variable R|<local>/x|"];
   113 [shape=box label="Function call: R|<local>/x|.R|/A.foo|()"];
   114 [shape=box label="Exit block"];
-  115 [shape=box label="Exit function test_3"];
+  115 [shape=box label="Exit function test_3" style="filled"];
 
   68 -> {69};
   69 -> {70};
@@ -252,8 +252,8 @@ subgraph test_3 {
   114 -> {115};
 }
 
-subgraph test_4 {
-  116 [shape=box label="Enter function test_4"];
+subgraph cluster_test_4 {
+  116 [shape=box label="Enter function test_4" style="filled"];
   117 [shape=box label="Enter block"];
   118 [shape=box label="Enter while loop"];
   119 [shape=box label="Enter loop condition"];
@@ -287,7 +287,7 @@ subgraph test_4 {
   147 [shape=box label="Access variable R|<local>/x|"];
   148 [shape=box label="Function call: R|<local>/x|.<Unresolved name: foo>#()"];
   149 [shape=box label="Exit block"];
-  150 [shape=box label="Exit function test_4"];
+  150 [shape=box label="Exit function test_4" style="filled"];
 
   116 -> {117};
   117 -> {118};
@@ -328,8 +328,8 @@ subgraph test_4 {
   149 -> {150};
 }
 
-subgraph test_5 {
-  151 [shape=box label="Enter function test_5"];
+subgraph cluster_test_5 {
+  151 [shape=box label="Enter function test_5" style="filled"];
   152 [shape=box label="Enter block"];
   153 [shape=box label="Enter do-while loop"];
   154 [shape=box label="Enter loop block"];
@@ -361,7 +361,7 @@ subgraph test_5 {
   180 [shape=box label="Access variable R|<local>/x|"];
   181 [shape=box label="Function call: R|<local>/x|.R|/A.foo|()"];
   182 [shape=box label="Exit block"];
-  183 [shape=box label="Exit function test_5"];
+  183 [shape=box label="Exit function test_5" style="filled"];
 
   151 -> {152};
   152 -> {153};
@@ -399,8 +399,8 @@ subgraph test_5 {
   182 -> {183};
 }
 
-subgraph test_6 {
-  184 [shape=box label="Enter function test_6"];
+subgraph cluster_test_6 {
+  184 [shape=box label="Enter function test_6" style="filled"];
   185 [shape=box label="Enter block"];
   186 [shape=box label="Enter do-while loop"];
   187 [shape=box label="Enter loop block"];
@@ -432,7 +432,7 @@ subgraph test_6 {
   213 [shape=box label="Access variable R|<local>/x|"];
   214 [shape=box label="Function call: R|<local>/x|.R|/A.foo|()"];
   215 [shape=box label="Exit block"];
-  216 [shape=box label="Exit function test_6"];
+  216 [shape=box label="Exit function test_6" style="filled"];
 
   184 -> {185};
   185 -> {186};
@@ -470,8 +470,8 @@ subgraph test_6 {
   215 -> {216};
 }
 
-subgraph test_7 {
-  217 [shape=box label="Enter function test_7"];
+subgraph cluster_test_7 {
+  217 [shape=box label="Enter function test_7" style="filled"];
   218 [shape=box label="Enter block"];
   219 [shape=box label="Enter do-while loop"];
   220 [shape=box label="Enter loop block"];
@@ -488,7 +488,7 @@ subgraph test_7 {
   231 [shape=box label="Access variable R|<local>/x|[DEAD]"];
   232 [shape=box label="Function call: R|<local>/x|.<Unresolved name: foo>#()[DEAD]"];
   233 [shape=box label="Exit block[DEAD]"];
-  234 [shape=box label="Exit function test_7[DEAD]"];
+  234 [shape=box label="Exit function test_7[DEAD]" style="filled"];
 
   217 -> {218};
   218 -> {219};
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/equalsAndIdentity.dot b/compiler/fir/resolve/testData/resolve/smartcasts/equalsAndIdentity.dot
index 789e5a92e62..8908f0882ea 100644
--- a/compiler/fir/resolve/testData/resolve/smartcasts/equalsAndIdentity.dot
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/equalsAndIdentity.dot
@@ -1,15 +1,15 @@
 digraph equalsAndIdentity_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph foo {
-  0 [shape=box label="Enter function foo"];
-  1 [shape=box label="Exit function foo"];
+subgraph cluster_foo {
+  0 [shape=box label="Enter function foo" style="filled"];
+  1 [shape=box label="Exit function foo" style="filled"];
 
   0 -> {1};
 }
 
-subgraph test_1 {
-  2 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  2 [shape=box label="Enter function test_1" style="filled"];
   3 [shape=box label="Enter block"];
   4 [shape=box label="Enter when"];
   5 [shape=box label="Enter when branch condition "];
@@ -50,7 +50,7 @@ subgraph test_1 {
   40 [shape=box label="Exit when branch result"];
   41 [shape=box label="Exit when"];
   42 [shape=box label="Exit block"];
-  43 [shape=box label="Exit function test_1"];
+  43 [shape=box label="Exit function test_1" style="filled"];
 
   2 -> {3};
   3 -> {4};
@@ -95,8 +95,8 @@ subgraph test_1 {
   42 -> {43};
 }
 
-subgraph test_2 {
-  44 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  44 [shape=box label="Enter function test_2" style="filled"];
   45 [shape=box label="Enter block"];
   46 [shape=box label="Enter when"];
   47 [shape=box label="Enter when branch condition "];
@@ -137,7 +137,7 @@ subgraph test_2 {
   82 [shape=box label="Exit when branch result"];
   83 [shape=box label="Exit when"];
   84 [shape=box label="Exit block"];
-  85 [shape=box label="Exit function test_2"];
+  85 [shape=box label="Exit function test_2" style="filled"];
 
   44 -> {45};
   45 -> {46};
@@ -182,8 +182,8 @@ subgraph test_2 {
   84 -> {85};
 }
 
-subgraph test_3 {
-  86 [shape=box label="Enter function test_3"];
+subgraph cluster_test_3 {
+  86 [shape=box label="Enter function test_3" style="filled"];
   87 [shape=box label="Enter block"];
   88 [shape=box label="Enter when"];
   89 [shape=box label="Enter when branch condition "];
@@ -241,7 +241,7 @@ subgraph test_3 {
   141 [shape=box label="Exit when branch result"];
   142 [shape=box label="Exit when"];
   143 [shape=box label="Exit block"];
-  144 [shape=box label="Exit function test_3"];
+  144 [shape=box label="Exit function test_3" style="filled"];
 
   86 -> {87};
   87 -> {88};
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.dot b/compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.dot
index acc2eeadb53..f0a8fdeace4 100644
--- a/compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.dot
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/equalsToBoolean.dot
@@ -1,22 +1,22 @@
 digraph equalsToBoolean_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph foo {
-  0 [shape=box label="Enter function foo"];
-  1 [shape=box label="Exit function foo"];
+subgraph cluster_foo {
+  0 [shape=box label="Enter function foo" style="filled"];
+  1 [shape=box label="Exit function foo" style="filled"];
 
   0 -> {1};
 }
 
-subgraph val_b {
-  2 [shape=box label="Enter property"];
-  3 [shape=box label="Exit property"];
+subgraph cluster_val_b {
+  2 [shape=box label="Enter property" style="filled"];
+  3 [shape=box label="Exit property" style="filled"];
 
   2 -> {3};
 }
 
-subgraph test_1 {
-  4 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  4 [shape=box label="Enter function test_1" style="filled"];
   5 [shape=box label="Enter block"];
   6 [shape=box label="Enter when"];
   7 [shape=box label="Enter when branch condition "];
@@ -40,7 +40,7 @@ subgraph test_1 {
   25 [shape=box label="Exit when branch result"];
   26 [shape=box label="Exit when"];
   27 [shape=box label="Exit block"];
-  28 [shape=box label="Exit function test_1"];
+  28 [shape=box label="Exit function test_1" style="filled"];
 
   4 -> {5};
   5 -> {6};
@@ -68,8 +68,8 @@ subgraph test_1 {
   27 -> {28};
 }
 
-subgraph test_2 {
-  29 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  29 [shape=box label="Enter function test_2" style="filled"];
   30 [shape=box label="Enter block"];
   31 [shape=box label="Enter when"];
   32 [shape=box label="Enter when branch condition "];
@@ -93,7 +93,7 @@ subgraph test_2 {
   50 [shape=box label="Exit when branch result"];
   51 [shape=box label="Exit when"];
   52 [shape=box label="Exit block"];
-  53 [shape=box label="Exit function test_2"];
+  53 [shape=box label="Exit function test_2" style="filled"];
 
   29 -> {30};
   30 -> {31};
@@ -121,8 +121,8 @@ subgraph test_2 {
   52 -> {53};
 }
 
-subgraph test_3 {
-  54 [shape=box label="Enter function test_3"];
+subgraph cluster_test_3 {
+  54 [shape=box label="Enter function test_3" style="filled"];
   55 [shape=box label="Enter block"];
   56 [shape=box label="Enter when"];
   57 [shape=box label="Enter when branch condition "];
@@ -146,7 +146,7 @@ subgraph test_3 {
   75 [shape=box label="Exit when branch result"];
   76 [shape=box label="Exit when"];
   77 [shape=box label="Exit block"];
-  78 [shape=box label="Exit function test_3"];
+  78 [shape=box label="Exit function test_3" style="filled"];
 
   54 -> {55};
   55 -> {56};
@@ -174,8 +174,8 @@ subgraph test_3 {
   77 -> {78};
 }
 
-subgraph test_4 {
-  79 [shape=box label="Enter function test_4"];
+subgraph cluster_test_4 {
+  79 [shape=box label="Enter function test_4" style="filled"];
   80 [shape=box label="Enter block"];
   81 [shape=box label="Enter when"];
   82 [shape=box label="Enter when branch condition "];
@@ -199,7 +199,7 @@ subgraph test_4 {
   100 [shape=box label="Exit when branch result"];
   101 [shape=box label="Exit when"];
   102 [shape=box label="Exit block"];
-  103 [shape=box label="Exit function test_4"];
+  103 [shape=box label="Exit function test_4" style="filled"];
 
   79 -> {80};
   80 -> {81};
@@ -227,8 +227,8 @@ subgraph test_4 {
   102 -> {103};
 }
 
-subgraph test_5 {
-  104 [shape=box label="Enter function test_5"];
+subgraph cluster_test_5 {
+  104 [shape=box label="Enter function test_5" style="filled"];
   105 [shape=box label="Enter block"];
   106 [shape=box label="Enter when"];
   107 [shape=box label="Enter when branch condition "];
@@ -252,7 +252,7 @@ subgraph test_5 {
   125 [shape=box label="Exit when branch result"];
   126 [shape=box label="Exit when"];
   127 [shape=box label="Exit block"];
-  128 [shape=box label="Exit function test_5"];
+  128 [shape=box label="Exit function test_5" style="filled"];
 
   104 -> {105};
   105 -> {106};
@@ -280,8 +280,8 @@ subgraph test_5 {
   127 -> {128};
 }
 
-subgraph test_6 {
-  129 [shape=box label="Enter function test_6"];
+subgraph cluster_test_6 {
+  129 [shape=box label="Enter function test_6" style="filled"];
   130 [shape=box label="Enter block"];
   131 [shape=box label="Enter when"];
   132 [shape=box label="Enter when branch condition "];
@@ -305,7 +305,7 @@ subgraph test_6 {
   150 [shape=box label="Exit when branch result"];
   151 [shape=box label="Exit when"];
   152 [shape=box label="Exit block"];
-  153 [shape=box label="Exit function test_6"];
+  153 [shape=box label="Exit function test_6" style="filled"];
 
   129 -> {130};
   130 -> {131};
@@ -333,8 +333,8 @@ subgraph test_6 {
   152 -> {153};
 }
 
-subgraph test_7 {
-  154 [shape=box label="Enter function test_7"];
+subgraph cluster_test_7 {
+  154 [shape=box label="Enter function test_7" style="filled"];
   155 [shape=box label="Enter block"];
   156 [shape=box label="Enter when"];
   157 [shape=box label="Enter when branch condition "];
@@ -358,7 +358,7 @@ subgraph test_7 {
   175 [shape=box label="Exit when branch result"];
   176 [shape=box label="Exit when"];
   177 [shape=box label="Exit block"];
-  178 [shape=box label="Exit function test_7"];
+  178 [shape=box label="Exit function test_7" style="filled"];
 
   154 -> {155};
   155 -> {156};
@@ -386,8 +386,8 @@ subgraph test_7 {
   177 -> {178};
 }
 
-subgraph test_8 {
-  179 [shape=box label="Enter function test_8"];
+subgraph cluster_test_8 {
+  179 [shape=box label="Enter function test_8" style="filled"];
   180 [shape=box label="Enter block"];
   181 [shape=box label="Enter when"];
   182 [shape=box label="Enter when branch condition "];
@@ -411,7 +411,7 @@ subgraph test_8 {
   200 [shape=box label="Exit when branch result"];
   201 [shape=box label="Exit when"];
   202 [shape=box label="Exit block"];
-  203 [shape=box label="Exit function test_8"];
+  203 [shape=box label="Exit function test_8" style="filled"];
 
   179 -> {180};
   180 -> {181};
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/inPlaceLambdas.dot b/compiler/fir/resolve/testData/resolve/smartcasts/inPlaceLambdas.dot
index 86e5a6f986d..1f9bc6c25ef 100644
--- a/compiler/fir/resolve/testData/resolve/smartcasts/inPlaceLambdas.dot
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/inPlaceLambdas.dot
@@ -1,26 +1,26 @@
 digraph inPlaceLambdas_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph foo {
-  0 [shape=box label="Enter function foo"];
-  1 [shape=box label="Exit function foo"];
+subgraph cluster_foo {
+  0 [shape=box label="Enter function foo" style="filled"];
+  1 [shape=box label="Exit function foo" style="filled"];
 
   0 -> {1};
 }
 
-subgraph bar {
-  2 [shape=box label="Enter function bar"];
-  3 [shape=box label="Exit function bar"];
+subgraph cluster_bar {
+  2 [shape=box label="Enter function bar" style="filled"];
+  3 [shape=box label="Exit function bar" style="filled"];
 
   2 -> {3};
 }
 
-subgraph run {
-  4 [shape=box label="Enter function run"];
+subgraph cluster_run {
+  4 [shape=box label="Enter function run" style="filled"];
   5 [shape=box label="Enter block"];
   6 [shape=box label="Function call: R|<local>/block|.R|FakeOverride<kotlin/Function0.invoke: R|kotlin/Unit|>|()"];
   7 [shape=box label="Exit block"];
-  8 [shape=box label="Exit function run"];
+  8 [shape=box label="Exit function run" style="filled"];
 
   4 -> {5};
   5 -> {6};
@@ -28,8 +28,8 @@ subgraph run {
   7 -> {8};
 }
 
-subgraph test_1 {
-  9 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  9 [shape=box label="Enter function test_1" style="filled"];
   10 [shape=box label="Enter block"];
   11 [shape=box label="Enter when"];
   12 [shape=box label="Enter when branch condition "];
@@ -56,7 +56,7 @@ subgraph test_1 {
   30 [shape=box label="Exit when branch result"];
   31 [shape=box label="Exit when"];
   32 [shape=box label="Exit block"];
-  33 [shape=box label="Exit function test_1"];
+  33 [shape=box label="Exit function test_1" style="filled"];
 
   9 -> {10};
   10 -> {11};
@@ -84,8 +84,8 @@ subgraph test_1 {
   32 -> {33};
 }
 
-subgraph test_2 {
-  34 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  34 [shape=box label="Enter function test_2" style="filled"];
   35 [shape=box label="Enter block"];
   36 [shape=box label="Enter function anonymousFunction"];
   37 [shape=box label="Enter block"];
@@ -100,7 +100,7 @@ subgraph test_2 {
   43 [shape=box label="Access variable R|<local>/x|"];
   44 [shape=box label="Function call: R|<local>/x|.R|/B.bar|()"];
   45 [shape=box label="Exit block"];
-  46 [shape=box label="Exit function test_2"];
+  46 [shape=box label="Exit function test_2" style="filled"];
 
   34 -> {35};
   35 -> {36};
@@ -116,8 +116,8 @@ subgraph test_2 {
   45 -> {46};
 }
 
-subgraph test_3 {
-  47 [shape=box label="Enter function test_3"];
+subgraph cluster_test_3 {
+  47 [shape=box label="Enter function test_3" style="filled"];
   48 [shape=box label="Enter block"];
   49 [shape=box label="Enter when"];
   50 [shape=box label="Enter when branch condition "];
@@ -149,7 +149,7 @@ subgraph test_3 {
   72 [shape=box label="Exit when branch result"];
   73 [shape=box label="Exit when"];
   74 [shape=box label="Exit block"];
-  75 [shape=box label="Exit function test_3"];
+  75 [shape=box label="Exit function test_3" style="filled"];
 
   47 -> {48};
   48 -> {49};
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/nullability.dot b/compiler/fir/resolve/testData/resolve/smartcasts/nullability.dot
index 6c8516e9b4a..4c9908fb49a 100644
--- a/compiler/fir/resolve/testData/resolve/smartcasts/nullability.dot
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/nullability.dot
@@ -1,50 +1,50 @@
 digraph nullability_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph foo {
-  0 [shape=box label="Enter function foo"];
-  1 [shape=box label="Exit function foo"];
+subgraph cluster_foo {
+  0 [shape=box label="Enter function foo" style="filled"];
+  1 [shape=box label="Exit function foo" style="filled"];
 
   0 -> {1};
 }
 
-subgraph getA {
-  2 [shape=box label="Enter function getA"];
-  3 [shape=box label="Exit function getA"];
+subgraph cluster_getA {
+  2 [shape=box label="Enter function getA" style="filled"];
+  3 [shape=box label="Exit function getA" style="filled"];
 
   2 -> {3};
 }
 
-subgraph val_s {
-  4 [shape=box label="Enter property"];
-  5 [shape=box label="Exit property"];
+subgraph cluster_val_s {
+  4 [shape=box label="Enter property" style="filled"];
+  5 [shape=box label="Exit property" style="filled"];
 
   4 -> {5};
 }
 
-subgraph fs {
-  6 [shape=box label="Enter function fs"];
-  7 [shape=box label="Exit function fs"];
+subgraph cluster_fs {
+  6 [shape=box label="Enter function fs" style="filled"];
+  7 [shape=box label="Exit function fs" style="filled"];
 
   6 -> {7};
 }
 
-subgraph val_data {
-  8 [shape=box label="Enter property"];
-  9 [shape=box label="Exit property"];
+subgraph cluster_val_data {
+  8 [shape=box label="Enter property" style="filled"];
+  9 [shape=box label="Exit property" style="filled"];
 
   8 -> {9};
 }
 
-subgraph fdata {
-  10 [shape=box label="Enter function fdata"];
-  11 [shape=box label="Exit function fdata"];
+subgraph cluster_fdata {
+  10 [shape=box label="Enter function fdata" style="filled"];
+  11 [shape=box label="Exit function fdata" style="filled"];
 
   10 -> {11};
 }
 
-subgraph test_1 {
-  12 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  12 [shape=box label="Enter function test_1" style="filled"];
   13 [shape=box label="Enter block"];
   14 [shape=box label="Enter when"];
   15 [shape=box label="Enter when branch condition "];
@@ -68,7 +68,7 @@ subgraph test_1 {
   33 [shape=box label="Access variable R|<local>/x|"];
   34 [shape=box label="Function call: R|<local>/x|.<Inapplicable(WRONG_RECEIVER): [/A.foo]>#()"];
   35 [shape=box label="Exit block"];
-  36 [shape=box label="Exit function test_1"];
+  36 [shape=box label="Exit function test_1" style="filled"];
 
   12 -> {13};
   13 -> {14};
@@ -96,8 +96,8 @@ subgraph test_1 {
   35 -> {36};
 }
 
-subgraph test_2 {
-  37 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  37 [shape=box label="Enter function test_2" style="filled"];
   38 [shape=box label="Enter block"];
   39 [shape=box label="Enter when"];
   40 [shape=box label="Enter when branch condition "];
@@ -121,7 +121,7 @@ subgraph test_2 {
   58 [shape=box label="Access variable R|<local>/x|"];
   59 [shape=box label="Function call: R|<local>/x|.<Inapplicable(WRONG_RECEIVER): [/A.foo]>#()"];
   60 [shape=box label="Exit block"];
-  61 [shape=box label="Exit function test_2"];
+  61 [shape=box label="Exit function test_2" style="filled"];
 
   37 -> {38};
   38 -> {39};
@@ -149,8 +149,8 @@ subgraph test_2 {
   60 -> {61};
 }
 
-subgraph test_3 {
-  62 [shape=box label="Enter function test_3"];
+subgraph cluster_test_3 {
+  62 [shape=box label="Enter function test_3" style="filled"];
   63 [shape=box label="Enter block"];
   64 [shape=box label="Enter when"];
   65 [shape=box label="Access variable R|<local>/x|"];
@@ -174,7 +174,7 @@ subgraph test_3 {
   83 [shape=box label="Access variable R|<local>/x|"];
   84 [shape=box label="Function call: R|<local>/x|.R|/A.foo|()"];
   85 [shape=box label="Exit block"];
-  86 [shape=box label="Exit function test_3"];
+  86 [shape=box label="Exit function test_3" style="filled"];
 
   62 -> {63};
   63 -> {64};
@@ -203,8 +203,8 @@ subgraph test_3 {
   85 -> {86};
 }
 
-subgraph test_4 {
-  87 [shape=box label="Enter function test_4"];
+subgraph cluster_test_4 {
+  87 [shape=box label="Enter function test_4" style="filled"];
   88 [shape=box label="Enter block"];
   89 [shape=box label="Enter when"];
   90 [shape=box label="Enter when branch condition "];
@@ -227,7 +227,7 @@ subgraph test_4 {
   107 [shape=box label="Access variable R|<local>/x|"];
   108 [shape=box label="Function call: R|<local>/x|.R|/A.foo|()"];
   109 [shape=box label="Exit block"];
-  110 [shape=box label="Exit function test_4"];
+  110 [shape=box label="Exit function test_4" style="filled"];
 
   87 -> {88};
   88 -> {89};
@@ -255,8 +255,8 @@ subgraph test_4 {
   109 -> {110};
 }
 
-subgraph test_5 {
-  111 [shape=box label="Enter function test_5"];
+subgraph cluster_test_5 {
+  111 [shape=box label="Enter function test_5" style="filled"];
   112 [shape=box label="Enter block"];
   113 [shape=box label="Enter when"];
   114 [shape=box label="Enter when branch condition "];
@@ -286,7 +286,7 @@ subgraph test_5 {
   138 [shape=box label="Exit when branch result"];
   139 [shape=box label="Exit when"];
   140 [shape=box label="Exit block"];
-  141 [shape=box label="Exit function test_5"];
+  141 [shape=box label="Exit function test_5" style="filled"];
 
   111 -> {112};
   112 -> {113};
@@ -320,8 +320,8 @@ subgraph test_5 {
   140 -> {141};
 }
 
-subgraph test_6 {
-  142 [shape=box label="Enter function test_6"];
+subgraph cluster_test_6 {
+  142 [shape=box label="Enter function test_6" style="filled"];
   143 [shape=box label="Enter block"];
   144 [shape=box label="Enter when"];
   145 [shape=box label="Access variable R|<local>/q|"];
@@ -355,7 +355,7 @@ subgraph test_6 {
   173 [shape=box label="Access variable R|/MyData.s|"];
   174 [shape=box label="Function call: R|<local>/q|.R|/Q.data|.R|/MyData.s|.R|kotlin/Int.inc|()"];
   175 [shape=box label="Exit block"];
-  176 [shape=box label="Exit function test_6"];
+  176 [shape=box label="Exit function test_6" style="filled"];
 
   142 -> {143};
   143 -> {144};
@@ -394,8 +394,8 @@ subgraph test_6 {
   175 -> {176};
 }
 
-subgraph test_7 {
-  177 [shape=box label="Enter function test_7"];
+subgraph cluster_test_7 {
+  177 [shape=box label="Enter function test_7" style="filled"];
   178 [shape=box label="Enter block"];
   179 [shape=box label="Enter when"];
   180 [shape=box label="Enter when branch condition "];
@@ -425,7 +425,7 @@ subgraph test_7 {
   204 [shape=box label="Exit when branch result"];
   205 [shape=box label="Exit when"];
   206 [shape=box label="Exit block"];
-  207 [shape=box label="Exit function test_7"];
+  207 [shape=box label="Exit function test_7" style="filled"];
 
   177 -> {178};
   178 -> {179};
@@ -459,8 +459,8 @@ subgraph test_7 {
   206 -> {207};
 }
 
-subgraph test_8 {
-  208 [shape=box label="Enter function test_8"];
+subgraph cluster_test_8 {
+  208 [shape=box label="Enter function test_8" style="filled"];
   209 [shape=box label="Enter block"];
   210 [shape=box label="Enter when"];
   211 [shape=box label="Enter when branch condition "];
@@ -480,7 +480,7 @@ subgraph test_8 {
   225 [shape=box label="Exit when branch result"];
   226 [shape=box label="Exit when"];
   227 [shape=box label="Exit block"];
-  228 [shape=box label="Exit function test_8"];
+  228 [shape=box label="Exit function test_8" style="filled"];
 
   208 -> {209};
   209 -> {210};
@@ -504,8 +504,8 @@ subgraph test_8 {
   227 -> {228};
 }
 
-subgraph test_9 {
-  229 [shape=box label="Enter function test_9"];
+subgraph cluster_test_9 {
+  229 [shape=box label="Enter function test_9" style="filled"];
   230 [shape=box label="Enter block"];
   231 [shape=box label="Enter when"];
   232 [shape=box label="Enter when branch condition "];
@@ -584,7 +584,7 @@ subgraph test_9 {
   305 [shape=box label="Access variable R|<local>/b|"];
   306 [shape=box label="Function call: R|<local>/b|.<Ambiguity: inc, [kotlin/inc, kotlin/inc]>#()"];
   307 [shape=box label="Exit block"];
-  308 [shape=box label="Exit function test_9"];
+  308 [shape=box label="Exit function test_9" style="filled"];
 
   229 -> {230};
   230 -> {231};
@@ -667,8 +667,8 @@ subgraph test_9 {
   307 -> {308};
 }
 
-subgraph test_10 {
-  309 [shape=box label="Enter function test_10"];
+subgraph cluster_test_10 {
+  309 [shape=box label="Enter function test_10" style="filled"];
   310 [shape=box label="Enter block"];
   311 [shape=box label="Enter when"];
   312 [shape=box label="Enter when branch condition "];
@@ -747,7 +747,7 @@ subgraph test_10 {
   385 [shape=box label="Access variable R|<local>/b|"];
   386 [shape=box label="Function call: R|<local>/b|.<Ambiguity: inc, [kotlin/inc, kotlin/inc]>#()"];
   387 [shape=box label="Exit block"];
-  388 [shape=box label="Exit function test_10"];
+  388 [shape=box label="Exit function test_10" style="filled"];
 
   309 -> {310};
   310 -> {311};
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/returns.dot b/compiler/fir/resolve/testData/resolve/smartcasts/returns.dot
index 8917b48bc47..32885c08b9f 100644
--- a/compiler/fir/resolve/testData/resolve/smartcasts/returns.dot
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/returns.dot
@@ -1,8 +1,8 @@
 digraph returns_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph test_0 {
-  0 [shape=box label="Enter function test_0"];
+subgraph cluster_test_0 {
+  0 [shape=box label="Enter function test_0" style="filled"];
   1 [shape=box label="Enter block"];
   2 [shape=box label="Enter when"];
   3 [shape=box label="Enter when branch condition "];
@@ -23,7 +23,7 @@ subgraph test_0 {
   18 [shape=box label="Access variable R|<local>/x|"];
   19 [shape=box label="Access variable <Unresolved name: length>#"];
   20 [shape=box label="Exit block"];
-  21 [shape=box label="Exit function test_0"];
+  21 [shape=box label="Exit function test_0" style="filled"];
 
   0 -> {1};
   1 -> {2};
@@ -48,8 +48,8 @@ subgraph test_0 {
   20 -> {21};
 }
 
-subgraph test_1 {
-  22 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  22 [shape=box label="Enter function test_1" style="filled"];
   23 [shape=box label="Enter block"];
   24 [shape=box label="Enter when"];
   25 [shape=box label="Enter when branch condition "];
@@ -72,7 +72,7 @@ subgraph test_1 {
   42 [shape=box label="Access variable R|<local>/x|"];
   43 [shape=box label="Access variable R|kotlin/String.length|"];
   44 [shape=box label="Exit block"];
-  45 [shape=box label="Exit function test_1"];
+  45 [shape=box label="Exit function test_1" style="filled"];
 
   22 -> {23};
   23 -> {24};
@@ -100,29 +100,29 @@ subgraph test_1 {
   44 -> {45};
 }
 
-subgraph foo {
-  46 [shape=box label="Enter function foo"];
-  47 [shape=box label="Exit function foo"];
+subgraph cluster_foo {
+  46 [shape=box label="Enter function foo" style="filled"];
+  47 [shape=box label="Exit function foo" style="filled"];
 
   46 -> {47};
 }
 
-subgraph bar {
-  48 [shape=box label="Enter function bar"];
-  49 [shape=box label="Exit function bar"];
+subgraph cluster_bar {
+  48 [shape=box label="Enter function bar" style="filled"];
+  49 [shape=box label="Exit function bar" style="filled"];
 
   48 -> {49};
 }
 
-subgraph baz {
-  50 [shape=box label="Enter function baz"];
-  51 [shape=box label="Exit function baz"];
+subgraph cluster_baz {
+  50 [shape=box label="Enter function baz" style="filled"];
+  51 [shape=box label="Exit function baz" style="filled"];
 
   50 -> {51};
 }
 
-subgraph test_2 {
-  52 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  52 [shape=box label="Enter function test_2" style="filled"];
   53 [shape=box label="Enter block"];
   54 [shape=box label="Enter when"];
   55 [shape=box label="Enter when branch condition "];
@@ -158,7 +158,7 @@ subgraph test_2 {
   85 [shape=box label="Access variable R|<local>/x|"];
   86 [shape=box label="Function call: R|<local>/x|.<Unresolved name: baz>#()"];
   87 [shape=box label="Exit block"];
-  88 [shape=box label="Exit function test_2"];
+  88 [shape=box label="Exit function test_2" style="filled"];
 
   52 -> {53};
   53 -> {54};
@@ -199,8 +199,8 @@ subgraph test_2 {
   87 -> {88};
 }
 
-subgraph test_3 {
-  89 [shape=box label="Enter function test_3"];
+subgraph cluster_test_3 {
+  89 [shape=box label="Enter function test_3" style="filled"];
   90 [shape=box label="Enter block"];
   91 [shape=box label="Enter when"];
   92 [shape=box label="Enter when branch condition "];
@@ -234,7 +234,7 @@ subgraph test_3 {
   120 [shape=box label="Access variable R|<local>/x|"];
   121 [shape=box label="Function call: R|<local>/x|.<Unresolved name: baz>#()"];
   122 [shape=box label="Exit block"];
-  123 [shape=box label="Exit function test_3"];
+  123 [shape=box label="Exit function test_3" style="filled"];
 
   89 -> {90};
   90 -> {91};
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/simpleIf.dot b/compiler/fir/resolve/testData/resolve/smartcasts/simpleIf.dot
index b5f3da8b8aa..8f0a7603c38 100644
--- a/compiler/fir/resolve/testData/resolve/smartcasts/simpleIf.dot
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/simpleIf.dot
@@ -1,8 +1,8 @@
 digraph simpleIf_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph test_1 {
-  0 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  0 [shape=box label="Enter function test_1" style="filled"];
   1 [shape=box label="Enter block"];
   2 [shape=box label="Enter when"];
   3 [shape=box label="Enter when branch condition "];
@@ -23,7 +23,7 @@ subgraph test_1 {
   18 [shape=box label="Access variable R|<local>/x|"];
   19 [shape=box label="Access variable <Unresolved name: length>#"];
   20 [shape=box label="Exit block"];
-  21 [shape=box label="Exit function test_1"];
+  21 [shape=box label="Exit function test_1" style="filled"];
 
   0 -> {1};
   1 -> {2};
@@ -48,8 +48,8 @@ subgraph test_1 {
   20 -> {21};
 }
 
-subgraph test_2 {
-  22 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  22 [shape=box label="Enter function test_2" style="filled"];
   23 [shape=box label="Enter block"];
   24 [shape=box label="Access variable R|<local>/x|"];
   25 [shape=box label="Type operator: x is String"];
@@ -72,7 +72,7 @@ subgraph test_2 {
   42 [shape=box label="Access variable R|<local>/x|"];
   43 [shape=box label="Access variable <Unresolved name: length>#"];
   44 [shape=box label="Exit block"];
-  45 [shape=box label="Exit function test_2"];
+  45 [shape=box label="Exit function test_2" style="filled"];
 
   22 -> {23};
   23 -> {24};
@@ -99,8 +99,8 @@ subgraph test_2 {
   44 -> {45};
 }
 
-subgraph test_3 {
-  46 [shape=box label="Enter function test_3"];
+subgraph cluster_test_3 {
+  46 [shape=box label="Enter function test_3" style="filled"];
   47 [shape=box label="Enter block"];
   48 [shape=box label="Enter when"];
   49 [shape=box label="Enter when branch condition "];
@@ -128,7 +128,7 @@ subgraph test_3 {
   71 [shape=box label="Exit when branch result"];
   72 [shape=box label="Exit when"];
   73 [shape=box label="Exit block"];
-  74 [shape=box label="Exit function test_3"];
+  74 [shape=box label="Exit function test_3" style="filled"];
 
   46 -> {47};
   47 -> {48};
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/when.dot b/compiler/fir/resolve/testData/resolve/smartcasts/when.dot
index 8bd588084b6..bfa875d621e 100644
--- a/compiler/fir/resolve/testData/resolve/smartcasts/when.dot
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/when.dot
@@ -1,22 +1,22 @@
 digraph when_kt {
-graph [splines=ortho]
+graph [splines=ortho, nodesep=3]
 
-subgraph foo {
-  0 [shape=box label="Enter function foo"];
-  1 [shape=box label="Exit function foo"];
+subgraph cluster_foo {
+  0 [shape=box label="Enter function foo" style="filled"];
+  1 [shape=box label="Exit function foo" style="filled"];
 
   0 -> {1};
 }
 
-subgraph bar {
-  2 [shape=box label="Enter function bar"];
-  3 [shape=box label="Exit function bar"];
+subgraph cluster_bar {
+  2 [shape=box label="Enter function bar" style="filled"];
+  3 [shape=box label="Exit function bar" style="filled"];
 
   2 -> {3};
 }
 
-subgraph test_1 {
-  4 [shape=box label="Enter function test_1"];
+subgraph cluster_test_1 {
+  4 [shape=box label="Enter function test_1" style="filled"];
   5 [shape=box label="Enter block"];
   6 [shape=box label="Enter when"];
   7 [shape=box label="Enter when branch condition "];
@@ -84,7 +84,7 @@ subgraph test_1 {
   69 [shape=box label="Exit when branch result"];
   70 [shape=box label="Exit when"];
   71 [shape=box label="Exit block"];
-  72 [shape=box label="Exit function test_1"];
+  72 [shape=box label="Exit function test_1" style="filled"];
 
   4 -> {5};
   5 -> {6};
@@ -156,8 +156,8 @@ subgraph test_1 {
   71 -> {72};
 }
 
-subgraph test_2 {
-  73 [shape=box label="Enter function test_2"];
+subgraph cluster_test_2 {
+  73 [shape=box label="Enter function test_2" style="filled"];
   74 [shape=box label="Enter block"];
   75 [shape=box label="Enter when"];
   76 [shape=box label="Access variable R|<local>/x|"];
@@ -222,7 +222,7 @@ subgraph test_2 {
   135 [shape=box label="Exit when branch result"];
   136 [shape=box label="Exit when"];
   137 [shape=box label="Exit block"];
-  138 [shape=box label="Exit function test_2"];
+  138 [shape=box label="Exit function test_2" style="filled"];
 
   73 -> {74};
   74 -> {75};
@@ -291,8 +291,8 @@ subgraph test_2 {
   137 -> {138};
 }
 
-subgraph test_3 {
-  139 [shape=box label="Enter function test_3"];
+subgraph cluster_test_3 {
+  139 [shape=box label="Enter function test_3" style="filled"];
   140 [shape=box label="Enter block"];
   141 [shape=box label="Enter when"];
   142 [shape=box label="Access variable R|<local>/x|"];
@@ -375,7 +375,7 @@ subgraph test_3 {
   219 [shape=box label="Exit when branch result"];
   220 [shape=box label="Exit when"];
   221 [shape=box label="Exit block"];
-  222 [shape=box label="Exit function test_3"];
+  222 [shape=box label="Exit function test_3" style="filled"];
 
   139 -> {140};
   140 -> {141};
@@ -462,8 +462,8 @@ subgraph test_3 {
   221 -> {222};
 }
 
-subgraph test_4 {
-  223 [shape=box label="Enter function test_4"];
+subgraph cluster_test_4 {
+  223 [shape=box label="Enter function test_4" style="filled"];
   224 [shape=box label="Enter block"];
   225 [shape=box label="Enter when"];
   226 [shape=box label="Access variable R|<local>/x|"];
@@ -486,7 +486,7 @@ subgraph test_4 {
   243 [shape=box label="Access variable R|<local>/x|"];
   244 [shape=box label="Function call: R|<local>/x|.R|kotlin/Int.inc|()"];
   245 [shape=box label="Exit block"];
-  246 [shape=box label="Exit function test_4"];
+  246 [shape=box label="Exit function test_4" style="filled"];
 
   223 -> {224};
   224 -> {225};
diff --git a/compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/AbstractFirCfgBuildingTest.kt b/compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/AbstractFirCfgBuildingTest.kt
index 18ab3463d37..d659ba2be71 100644
--- a/compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/AbstractFirCfgBuildingTest.kt
+++ b/compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/AbstractFirCfgBuildingTest.kt
@@ -60,7 +60,7 @@ abstract class AbstractFirCfgBuildingTest : AbstractFirResolveTestCase() {
 
         override fun visitFile(file: FirFile) {
             dotBuilder.appendln("digraph ${file.name.replace(".", "_")} {")
-                .appendln("graph [splines=ortho]")
+                .appendln("graph [splines=ortho, nodesep=3]")
                 .appendln()
             super.visitFile(file)
             dotBuilder.appendln("}")
@@ -86,7 +86,8 @@ fun ControlFlowGraph.dotRenderToStringBuilder(builder: StringBuilder, indexOffse
     with(builder) {
         val sortedNodes = sortNodes()
         val indices = sortedNodes.indicesMap().mapValues { (_, index) -> index + indexOffset }
-        appendln("subgraph ${name.replace(" ", "_")} {")
+        val graphName = name.replace(Regex("[ <>]"), "_")
+        appendln("subgraph cluster_$graphName {")
 
         fun CFGNode<*>.splitEdges(): Pair<List<CFGNode<*>>, List<CFGNode<*>>> =
             if (isDead) emptyList<CFGNode<*>>() to followingNodes
@@ -95,7 +96,12 @@ fun ControlFlowGraph.dotRenderToStringBuilder(builder: StringBuilder, indexOffse
         sortedNodes.forEach {
             append(INDENT)
             append(indices.getValue(it))
-            appendln(" [shape=box label=\"${it.render().replace("\"", "")}\"];")
+            val attributes = mutableListOf("shape=box")
+            attributes += "label=\"${it.render().replace("\"", "")}\""
+            if (it == enterNode || it == exitNode) {
+                attributes += "style=\"filled\""
+            }
+            appendln(attributes.joinToString(separator = " ", prefix = " [", postfix = "];"))
         }
         appendln()