diff --git a/platform/platform-api/src/com/intellij/openapi/ui/DialogWrapper.java b/platform/platform-api/src/com/intellij/openapi/ui/DialogWrapper.java
index c41e22d63f44..feedf7f1d02e 100644
--- a/platform/platform-api/src/com/intellij/openapi/ui/DialogWrapper.java
+++ b/platform/platform-api/src/com/intellij/openapi/ui/DialogWrapper.java
@@ -1160,6 +1160,7 @@ public abstract class DialogWrapper {
   }
 
   protected void init() {
+    assert SwingUtilities.isEventDispatchThread() : "Dialog must be init in EDT only: "+Thread.currentThread();
     myErrorText = new ErrorText();
     myErrorText.setVisible(false);