diff --git a/platform/core-impl/src/com/intellij/openapi/editor/impl/DocumentImpl.java b/platform/core-impl/src/com/intellij/openapi/editor/impl/DocumentImpl.java
index 023b104585af..715ff4833c70 100644
--- a/platform/core-impl/src/com/intellij/openapi/editor/impl/DocumentImpl.java
+++ b/platform/core-impl/src/com/intellij/openapi/editor/impl/DocumentImpl.java
@@ -776,6 +776,7 @@ public class DocumentImpl extends UserDataHolderBase implements DocumentEx {
 
   @Override
   public final void setInBulkUpdate(boolean value) {
+    ApplicationManager.getApplication().assertIsDispatchThread();
     myDoingBulkUpdate = value;
     myText.setDeferredChangeMode(value);
     if (value) {