Bug 138562 Splite extendsexcpetion to seperate sub class
The suggestion is Parent invalid Cycle extends Different type extends Not top level extends
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
if ( derived != null )
		{
			
			
			if ( ev.getDeliveryPath( ) == NotificationEvent.ELEMENT_CLIENT )
				return;
			
			
			
			
			
			if ( ev.getDeliveryPath( ) != NotificationEvent.STYLE_CLIENT )
				ev.setDeliveryPath( NotificationEvent.DESCENDENT );
			Iterator iter = derived.iterator( );
			while ( iter.hasNext( ) )
			{
				( (DesignElement) iter.next( ) ).broadcast( ev, module );
			}
		}
	}
	/**
	 * Returns <code>true</code> if the element is within a child element
	 * which extends from another. Returns <code>false</code> otherwise. <br>
	 * <strong>Notice: </strong> <br>
	 * If the element is a virtual element, it must have defined a <code>
	 * baseId<code> which point to the ID of its virtual parent. 
	 * 
	 * @return Returns <code>true</code> if the element is within a child element
	 * which extends from another.
	 */