Bug 124620 Referenced Parameter icon should be invalid if the parameter in library is deleted
Description: Referenced parameter icon should be invalid if the source parameter in library is deleted. Steps to reproduce: 1.Create a library. Insert a report scalar parameter. 2.Create a report, use the above library. In the library explorer, pull the parameter to the data explorer view of report. 3.Open the library file, delete the parameter. Then reopen the report design file, the icon of parameter seems nothing happened. But if those operations happened in dataset, the icon of dataset in the report will be invalid. It is acceptable. Expected Result: The icon of referenced parameter should be invalid.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
public void clearListeners( )
	{
		if ( listeners != null )
			listeners.clear( );
		listeners = null;
	}
	/**
	 * Sends an event called by the notification framework. The default
	 * implementation sends the event to listeners of this one object. Derived
	 * classes override this to send it to additional associated objects
	 * depending on context. The subclass should set the event's delivery path
	 * to indicate these additional delivery routes.
	 * <p>
	 * Part of: Notification system.
	 * 
	 * @param ev
	 *            the event to send
	 */
	public void sendEvent( NotificationEvent ev )
	{
		ev.setDeliveryPath( NotificationEvent.DIRECT );
		broadcast( ev );
	}
	/**
	 * Gets the root node of the design tree. This node must be a instance of
	 * <code>ReportDesign</code> or <code>Library</code>.
	 * 
	 * @return the root node of the design tree
	 */
	public Module getRoot( )