EA-67407 - assert: AbstractTreeUi._expand - add logging

xml/dom-impl/src/com/intellij/util/xml/structure/DomStructureViewTreeModel.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2014 JetBrains s.r.o.
+ * Copyright 2000-2015 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -60,4 +60,9 @@ public class DomStructureViewTreeModel extends XmlStructureViewTreeModel impleme
   protected DomElementNavigationProvider getNavigationProvider() {
     return myNavigationProvider;
   }
+
+  @Override
+  public String toString() {
+    return super.toString() + "; file: " + getPsiFile();
+  }
 }