diff --git a/platform/platform-impl/src/com/intellij/internal/ToggleLaggingModeAction.java b/platform/platform-impl/src/com/intellij/internal/ToggleLaggingModeAction.java
new file mode 100644
index 000000000000..f2c1bedf295f
--- /dev/null
+++ b/platform/platform-impl/src/com/intellij/internal/ToggleLaggingModeAction.java
@@ -0,0 +1,72 @@
+/*
+ * 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.internal;
+
+import com.intellij.ide.caches.CacheUpdater;
+import com.intellij.ide.caches.FileContent;
+import com.intellij.openapi.actionSystem.AnAction;
+import com.intellij.openapi.actionSystem.AnActionEvent;
+import com.intellij.openapi.actionSystem.PlatformDataKeys;
+import com.intellij.openapi.actionSystem.Presentation;
+import com.intellij.openapi.progress.ProgressIndicator;
+import com.intellij.openapi.project.DumbAware;
+import com.intellij.openapi.project.DumbServiceImpl;
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.vfs.VirtualFile;
+import com.intellij.psi.impl.DebugUtil;
+import com.intellij.util.Alarm;
+import com.intellij.util.TimeoutUtil;
+
+import java.util.Arrays;
+
+/**
+ * @author peter
+ */
+public class ToggleLaggingModeAction extends AnAction implements DumbAware {
+  private volatile boolean myLagging = false;
+  private final Alarm myAlarm = new Alarm(Alarm.ThreadToUse.SWING_THREAD); 
+
+  public void actionPerformed(final AnActionEvent e) {
+    if (myLagging) {
+      myLagging = false;
+      myAlarm.cancelAllRequests();
+    }
+    else {
+      myLagging = true;
+      for (int i = 0; i < 100; i++) {
+        new Runnable() {
+          @Override
+          public void run() {
+            myAlarm.addRequest(this, 1);
+          }
+        }.run();
+      }
+    }
+  }
+
+  @Override
+  public void update(final AnActionEvent e) {
+    final Presentation presentation = e.getPresentation();
+    final Project project = PlatformDataKeys.PROJECT.getData(e.getDataContext());
+    presentation.setEnabled(project != null && myLagging == DumbServiceImpl.getInstance(project).isDumb());
+    if (myLagging) {
+      presentation.setText("Exit dumb mode");
+    }
+    else {
+      presentation.setText("Enter dumb mode");
+    }
+  }
+}
diff --git a/platform/platform-resources/src/idea/PlatformActions.xml b/platform/platform-resources/src/idea/PlatformActions.xml
index 995dd9afa8e4..705b8f7f9599 100644
--- a/platform/platform-resources/src/idea/PlatformActions.xml
+++ b/platform/platform-resources/src/idea/PlatformActions.xml
@@ -537,6 +537,7 @@
       <action internal="true" id="PruneEmptyDirectories" class="com.intellij.ide.actions.PruneEmptyDirectoriesAction" text="Prune Empty Directories"/>
       <action internal="true" id="FixLineSeparators" class="com.intellij.ide.actions.FixLineSeparatorsAction" text="Fix Line Separators"/>
       <action id="DumbMode" internal="true" class="com.intellij.internal.ToggleDumbModeAction" text="Dumb mode"/>
+      <action id="LaggingMode" internal="true" class="com.intellij.internal.ToggleLaggingModeAction" text="Lagging mode"/>
       <separator/>
       <action id="NotificationTestAction" internal="true" class="com.intellij.notification.impl.actions.NotificationTestAction"
               text="Add Test Notification"/>