src/share/tools/IdealGraphVisualizer/Data/src/com/sun/hotspot/igv/data/GraphDocument.java

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2008, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.

@@ -49,15 +49,17 @@
     public ChangedEvent<GraphDocument> getChangedEvent() {
         return changedEvent;
     }
 
     public void addGraphDocument(GraphDocument document) {
+        if (document != this) {
         for (FolderElement e : document.elements) {
             e.setParent(this);
             this.addElement(e);
         }
         document.clear();
+        }
         getChangedEvent().fire();
     }
 
     @Override
     public String toString() {