Bug 122850 Table/list should not be able to be inserted in Master Page mode.
Description: Table/list should not be able to be inserted in Master Page mode. Steps to reproduce: 1. New a report and transfer to Master Page mode. 2. New a datasource and dataset 3. Drag a list/table to page header/footer, bind it to dataset and drag some columns inside. 4. Save and preview Expected result: Insert list/table item in master page should be forbidden. Actual result: They are allowed and preview showed "undefine" in page
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
if ( posn != -1 )
			listeners.remove( posn );
	}
	/**
	 * Removes all listeners on this element.
	 * <p>
	 * Part of: Notification system.
	 */
	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 );