diff --git a/platform/lang-impl/src/com/intellij/refactoring/changeSignature/ChangeSignatureGestureDetector.java b/platform/lang-impl/src/com/intellij/refactoring/changeSignature/ChangeSignatureGestureDetector.java
index 189f15b8742a..0caed03d9f5c 100644
--- a/platform/lang-impl/src/com/intellij/refactoring/changeSignature/ChangeSignatureGestureDetector.java
+++ b/platform/lang-impl/src/com/intellij/refactoring/changeSignature/ChangeSignatureGestureDetector.java
@@ -199,7 +199,9 @@ public class ChangeSignatureGestureDetector extends PsiTreeChangeAdapter impleme
       if (changeBean != null && changeBean.getInitialText() != null) {
         final Editor editor = myFileEditorManager.getSelectedTextEditor();
         if (editor != null && myTemplateManager.getActiveTemplate(editor) != null) return;
-        if (LanguageChangeSignatureDetectors.INSTANCE.forLanguage(child.getLanguage()).ignoreChanges(child)) return;
+        final LanguageChangeSignatureDetector detector = LanguageChangeSignatureDetectors.INSTANCE.forLanguage(child.getLanguage());
+        if (detector == null) return;
+        if (detector.ignoreChanges(child)) return;
         final ChangeInfo info = LanguageChangeSignatureDetectors.createCurrentChangeInfo(child, changeBean.getInitialChangeInfo());
         if (info == null) {
           changeBean.reinit();