diff --git a/platform/lang-impl/src/com/intellij/codeInsight/lookup/impl/CompletionExtender.java b/platform/lang-impl/src/com/intellij/codeInsight/lookup/impl/CompletionExtender.java
new file mode 100644
index 000000000000..824f89dc6392
--- /dev/null
+++ b/platform/lang-impl/src/com/intellij/codeInsight/lookup/impl/CompletionExtender.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright 2000-2012 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 com.intellij.codeInsight.lookup.impl;
+
+import com.intellij.codeInsight.lookup.LookupElement;
+import com.intellij.ui.HeavyweightHint;
+import com.intellij.ui.HintHint;
+import com.intellij.util.ui.UIUtil;
+import org.jetbrains.annotations.NotNull;
+
+import javax.swing.*;
+import java.awt.*;
+
+/**
+ * @author Konstantin Bulenkov
+ */
+public class CompletionExtender extends HeavyweightHint {
+  private LookupElement myElement;
+  @NotNull private LookupImpl myLookup;
+  private int myIndex;
+
+  public CompletionExtender(@NotNull LookupElement element, @NotNull LookupImpl lookup) {
+    super(createComponent(element, lookup), false);
+    myElement = element;
+    myLookup = lookup;
+    myIndex = myLookup.getList().getSelectedIndex();
+  }
+
+  public LookupElement getLookupElement() {
+    return myElement;
+  }
+
+  public boolean sameAsFor(LookupElement item) {
+    return getLookupElement().equals(item)
+           && myIndex == myLookup.getList().getSelectedIndex();
+  }
+
+  private static JComponent createComponent(LookupElement element, LookupImpl lookup) {
+    final LookupCellRenderer renderer = new LookupCellRenderer(lookup);
+    renderer.setFullSize(true);
+    final JComponent component = (JComponent)renderer.getListCellRendererComponent(lookup.getList(), element,
+                                                                                   lookup.getList().getSelectedIndex(),
+                                                                                   true, false);
+    component.setSize(component.getPreferredSize());
+    return component;
+  }
+
+  public boolean show() {
+    final JList list = myLookup.getList();
+    if (getComponent().getWidth() > list.getWidth()) {
+      final JComponent rootPane = UIUtil.getRootPane(myLookup.getEditor().getContentComponent());
+
+      final Point p = list.getLocationOnScreen();
+      p.y += list.indexToLocation(list.getSelectedIndex()).y;
+      SwingUtilities.convertPointFromScreen(p, rootPane);
+
+      if (rootPane != null) {
+        show(rootPane, p.x, p.y, null, new HintHint(rootPane, p));
+        return true;
+      }
+    }
+    return false;
+  }
+
+  private static Point getPoint(JList list, JComponent rootPane) {
+    final Point p = list.getLocationOnScreen();
+    p.y += list.indexToLocation(list.getSelectedIndex()).y;
+    SwingUtilities.convertPointFromScreen(p, rootPane);
+    return p;
+  }
+
+  @Override
+  public void hide() {
+    super.hide();
+    myLookup = null;
+    myElement = null;
+  }
+}
diff --git a/platform/lang-impl/src/com/intellij/codeInsight/lookup/impl/LookupImpl.java b/platform/lang-impl/src/com/intellij/codeInsight/lookup/impl/LookupImpl.java
index b11b7ef36300..a7c31b5a67dc 100644
--- a/platform/lang-impl/src/com/intellij/codeInsight/lookup/impl/LookupImpl.java
+++ b/platform/lang-impl/src/com/intellij/codeInsight/lookup/impl/LookupImpl.java
@@ -95,7 +95,7 @@ public class LookupImpl extends LightweightHint implements LookupEx, Disposable
 
   private final Project myProject;
   private final Editor myEditor;
-  private Hint tip;
+  private CompletionExtender extender;
   private String myInitialPrefix;
 
   private boolean myStableStart;
@@ -1029,10 +1029,6 @@ public class LookupImpl extends LightweightHint implements LookupEx, Disposable
       public void valueChanged(ListSelectionEvent e){
         myHintAlarm.cancelAllRequests();
 
-        if (tip != null && tip.isVisible()) {
-          tip.hide();
-        }
-
         final LookupElement item = getCurrentItem();
         if (oldItem != item) {
           mySelectionInvariant = item == null ? null : myPresentableModel.getItemPresentationInvariant(item);
@@ -1043,26 +1039,18 @@ public class LookupImpl extends LightweightHint implements LookupEx, Disposable
         }
         if (item != null) {
           updateHint(item);
-          if (myList.getModel().getSize() > 1 && isVisible()) {
-            final LookupCellRenderer renderer = new LookupCellRenderer(LookupImpl.this);
-            renderer.setFullSize(true);
-            final JComponent component = (JComponent)renderer.getListCellRendererComponent(myList, item,
-                                                                                           myList
-                                                                                             .getSelectedIndex(),
-                                                                                           true, false);
-            component.setSize(component.getPreferredSize());
-            if (component.getWidth() > myList.getWidth()) {
-              tip = new HeavyweightHint(component, false);
-              final Point p = myList.getLocationOnScreen();
-              p.y += myList.indexToLocation(myList.getSelectedIndex()).y;
+        }
+        oldItem = item;
 
-              final JComponent editor = UIUtil.getRootPane(myEditor.getContentComponent());
-              SwingUtilities.convertPointFromScreen(p, editor);
-              tip.show(editor, p.x, p.y, null, new HintHint(editor, p));
+        if (item != null && LookupImpl.this.isVisible()) {
+          if (extender == null || !extender.isVisible() || !extender.sameAsFor(item)) {
+            if (extender != null) extender.hide();
+            extender = new CompletionExtender(item, LookupImpl.this);
+            if (!extender.show()) {
+              extender.hide();
             }
           }
         }
-        oldItem = item;
       }
     });
 
@@ -1390,8 +1378,8 @@ public class LookupImpl extends LightweightHint implements LookupEx, Disposable
     }
     Disposer.dispose(myProcessIcon);
     Disposer.dispose(myHintAlarm);
-    if (tip != null) {
-      tip.hide();
+    if (extender != null) {
+      extender.hide();
     }
     myDisposed = true;
     disposeTrace = DebugUtil.currentStackTrace() + "\n============";