diff --git a/platform/lang-impl/src/com/intellij/refactoring/changeSignature/MethodNodeBase.java b/platform/lang-impl/src/com/intellij/refactoring/changeSignature/MethodNodeBase.java
index 3550c4706e25..bc469581bbb3 100644
--- a/platform/lang-impl/src/com/intellij/refactoring/changeSignature/MethodNodeBase.java
+++ b/platform/lang-impl/src/com/intellij/refactoring/changeSignature/MethodNodeBase.java
@@ -85,6 +85,14 @@ public abstract class MethodNodeBase<M extends PsiElement> extends CheckedTreeNo
     return super.getChildCount();
   }
 
+  @Override
+  public boolean isLeaf() {
+    if (children == null) {
+      return false;
+    }
+    return super.isLeaf();
+  }
+
   @Override
   public int getIndex(TreeNode aChild) {
     buildChildren();