revert getActivityStack( ) method.

model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/activity/AbstractElementCommand.java

@@ -78,16 +78,4 @@ static protected int checkAndAdjustPosition( int oldPosn, int newPosn,
 
 		return newPosn;
 	}
-
-	//If the element is not added in to the Module, exclude from the activity stack.
-	public ActivityStack getActivityStack( )
-    {
-        Module root = element.getRoot( );
-        if ( root == null )
-        {
-        	//set null module to avoid clearing the name helper cache
-            return new ActivityStack( null );
-        }
-        return module.getActivityStack( );
-    }
 }