Bug 151959 inappropriate screen operation
steps to reproduce: - create a report - add a grid item (3x3) - switch to Outline view - expand the grid item to see its rows and cells - select the grid item, and drag it into any of its own cell expected behavior: - is it an invalid screen operation? if it is, it should be banned actual behavior: - the grid item was disappeared surprisingly
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
* 
	 * @param ev
	 *            the event to send
	 * @param module
	 *            the root node of the design tree.
	 */
	public void broadcast( NotificationEvent ev, Module module )
	{
		
		
		
		if ( listeners != null )
		{
			ArrayList tmpListeners = new ArrayList( listeners );
			Iterator iter = tmpListeners.iterator( );
			while ( iter.hasNext( ) )
			{
				( (Listener) iter.next( ) ).elementChanged(
						getHandle( module ), ev );
			}
		}
		
		if ( derived != null )
		{
			
			
			if ( ev.getDeliveryPath( ) == NotificationEvent.ELEMENT_CLIENT )
				return;