diff --git a/idea/src/org/jetbrains/jet/plugin/libraries/JetClsFileDecompiledPsiFileProvider.java b/idea/src/org/jetbrains/jet/plugin/libraries/JetClsFileDecompiledPsiFileProvider.java
index a7b1d6f6884..455e0e8179a 100644
--- a/idea/src/org/jetbrains/jet/plugin/libraries/JetClsFileDecompiledPsiFileProvider.java
+++ b/idea/src/org/jetbrains/jet/plugin/libraries/JetClsFileDecompiledPsiFileProvider.java
@@ -16,6 +16,7 @@
 
 package org.jetbrains.jet.plugin.libraries;
 
+import com.intellij.openapi.project.DumbService;
 import com.intellij.psi.ClsFileDecompiledPsiFileProvider;
 import com.intellij.psi.PsiFile;
 import com.intellij.psi.PsiJavaFile;
@@ -32,7 +33,7 @@ public class JetClsFileDecompiledPsiFileProvider implements ClsFileDecompiledPsi
     @Override
     public PsiFile getDecompiledPsiFile(@NotNull PsiJavaFile psiFile) {
         ClsFileImpl clsFile = (ClsFileImpl)psiFile;
-        if (JetDecompiledData.isKotlinFile(clsFile)) {
+        if (JetDecompiledData.isKotlinFile(clsFile) && !DumbService.isDumb(psiFile.getProject())) {
             return JetDecompiledData.getDecompiledData(clsFile).getJetFile();
         }
         return null;
diff --git a/idea/src/org/jetbrains/jet/plugin/libraries/JetContentBasedFileSubstitutor.java b/idea/src/org/jetbrains/jet/plugin/libraries/JetContentBasedFileSubstitutor.java
index 78666ae3631..476b205ed32 100644
--- a/idea/src/org/jetbrains/jet/plugin/libraries/JetContentBasedFileSubstitutor.java
+++ b/idea/src/org/jetbrains/jet/plugin/libraries/JetContentBasedFileSubstitutor.java
@@ -17,8 +17,10 @@
 package org.jetbrains.jet.plugin.libraries;
 
 import com.intellij.lang.Language;
+import com.intellij.openapi.fileEditor.FileDocumentManager;
 import com.intellij.openapi.fileTypes.ContentBasedClassFileProcessor;
 import com.intellij.openapi.fileTypes.SyntaxHighlighter;
+import com.intellij.openapi.project.DumbService;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.psi.PsiFile;
@@ -34,8 +36,22 @@ import org.jetbrains.jet.plugin.highlighter.JetHighlighter;
 public class JetContentBasedFileSubstitutor implements ContentBasedClassFileProcessor {
 
     @Override
-    public boolean isApplicable(@Nullable Project project, @NotNull VirtualFile file) {
-        return project != null && JetDecompiledData.isKotlinFile(project, file);
+    public boolean isApplicable(@Nullable Project project, @NotNull final VirtualFile file) {
+        if (project == null) {
+            return false;
+        }
+
+        if (DumbService.isDumb(project)) {
+            DumbService.getInstance(project).runWhenSmart(new Runnable() {
+                @Override
+                public void run() {
+                    FileDocumentManager.getInstance().reloadFiles(file);
+                }
+            });
+            return false;
+        }
+
+        return JetDecompiledData.isKotlinFile(project, file);
     }
 
     @NotNull