diff --git a/idea/src/META-INF/plugin.xml b/idea/src/META-INF/plugin.xml
index 4b3b4ac859a..25197fa32c1 100644
--- a/idea/src/META-INF/plugin.xml
+++ b/idea/src/META-INF/plugin.xml
@@ -21,6 +21,9 @@
       <component>
           <implementation-class>org.jetbrains.jet.plugin.references.StandardLibraryReferenceResolver</implementation-class>
       </component>
+      <component>
+          <implementation-class>org.jetbrains.jet.plugin.highlighter.DeclarationHintSupport</implementation-class>
+      </component>
   </project-components>
 
   <actions>
diff --git a/idea/src/org/jetbrains/jet/plugin/highlighter/DeclarationHintSupport.java b/idea/src/org/jetbrains/jet/plugin/highlighter/DeclarationHintSupport.java
new file mode 100644
index 00000000000..4b7636657c2
--- /dev/null
+++ b/idea/src/org/jetbrains/jet/plugin/highlighter/DeclarationHintSupport.java
@@ -0,0 +1,92 @@
+/*
+ * Copyright 2010-2012 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.jet.plugin.highlighter;
+
+import com.intellij.codeInsight.hint.HintManager;
+import com.intellij.codeInsight.hint.HintManagerImpl;
+import com.intellij.codeInsight.hint.HintUtil;
+import com.intellij.openapi.components.AbstractProjectComponent;
+import com.intellij.openapi.editor.Editor;
+import com.intellij.openapi.editor.EditorFactory;
+import com.intellij.openapi.editor.event.EditorMouseEvent;
+import com.intellij.openapi.editor.event.EditorMouseEventArea;
+import com.intellij.openapi.editor.event.EditorMouseMotionAdapter;
+import com.intellij.openapi.project.Project;
+import com.intellij.psi.PsiDocumentManager;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiFile;
+import com.intellij.psi.util.PsiTreeUtil;
+import com.intellij.ui.LightweightHint;
+import org.jetbrains.jet.lang.descriptors.DeclarationDescriptor;
+import org.jetbrains.jet.lang.psi.JetFile;
+import org.jetbrains.jet.lang.psi.JetNamedDeclaration;
+import org.jetbrains.jet.lang.resolve.BindingContext;
+import org.jetbrains.jet.plugin.JetLanguage;
+import org.jetbrains.jet.plugin.project.WholeProjectAnalyzerFacade;
+import org.jetbrains.jet.resolve.DescriptorRenderer;
+
+import javax.swing.*;
+import java.awt.*;
+
+/**
+ * @author Evgeny Gerashchenko
+ * @since 5/16/12
+ */
+public class DeclarationHintSupport extends AbstractProjectComponent {
+    private final MyListener listener = new MyListener();
+
+    public DeclarationHintSupport(Project project) {
+        super(project);
+    }
+
+    @Override
+    public void initComponent() {
+        EditorFactory.getInstance().getEventMulticaster().addEditorMouseMotionListener(listener, myProject);
+    }
+
+    private class MyListener extends EditorMouseMotionAdapter {
+        @Override
+        public void mouseMoved(EditorMouseEvent e) {
+            if (e.isConsumed() || e.getArea() != EditorMouseEventArea.EDITING_AREA) return;
+
+            Editor editor = e.getEditor();
+            PsiFile psiFile = PsiDocumentManager.getInstance(myProject).getPsiFile(editor.getDocument());
+            if (psiFile == null || psiFile.getLanguage() != JetLanguage.INSTANCE) return;
+
+            JetFile jetFile = (JetFile) psiFile;
+
+            int offset = editor.logicalPositionToOffset(editor.xyToLogicalPosition(e.getMouseEvent().getPoint()));
+            PsiElement elementAtCursor = psiFile.findElementAt(offset);
+            JetNamedDeclaration declaration = PsiTreeUtil.getParentOfType(elementAtCursor, JetNamedDeclaration.class);
+            if (declaration != null && declaration.getNameIdentifier() == elementAtCursor) {
+                BindingContext bindingContext = WholeProjectAnalyzerFacade.analyzeProjectWithCacheOnAFile(jetFile).getBindingContext();
+
+                DeclarationDescriptor descriptor = bindingContext.get(BindingContext.DECLARATION_TO_DESCRIPTOR, declaration);
+
+                if (descriptor == null) {
+                    return;
+                }
+
+                JLayeredPane layeredPane = editor.getComponent().getRootPane().getLayeredPane();
+                Point point = SwingUtilities.convertPoint(e.getMouseEvent().getComponent(), e.getMouseEvent().getPoint(), layeredPane);
+                ((HintManagerImpl) HintManager.getInstance()).showEditorHint(
+                        new LightweightHint(HintUtil.createInformationLabel(DescriptorRenderer.HTML.render(descriptor))), editor, point,
+                        HintManager.HIDE_BY_ANY_KEY | HintManager.HIDE_BY_TEXT_CHANGE | HintManager.HIDE_BY_SCROLLING, 0, false);
+            }
+        }
+    }
+}