diff --git a/platform/platform-impl/src/com/intellij/openapi/diff/actions/IgnoreWhiteSpacesAction.java b/platform/platform-impl/src/com/intellij/openapi/diff/actions/IgnoreWhiteSpacesAction.java
index 78c5ba756923..6a68ad75d5d8 100644
--- a/platform/platform-impl/src/com/intellij/openapi/diff/actions/IgnoreWhiteSpacesAction.java
+++ b/platform/platform-impl/src/com/intellij/openapi/diff/actions/IgnoreWhiteSpacesAction.java
@@ -82,7 +82,7 @@ public class IgnoreWhiteSpacesAction extends ComboBoxAction implements DumbAware
     }
   }
 
-  private static class IgnoringPolicyAction extends AnAction {
+  private static class IgnoringPolicyAction extends AnAction implements DumbAware {
     private final ComparisonPolicy myPolicy;
 
     public IgnoringPolicyAction(String text, ComparisonPolicy policy) {