Bug 121352 The data set binding property cannot be retrieved in report preview layout
In report preview page, the datasource/dataset property binding lists cannot be retrieved. The dataset binding can not work correctly in layout preview because it's value cannot get from the binding list. But in the data set edit page, the binding value can be got. You can refer to the attachment.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
*            the listener to register
	 */
	public void addListener( Listener obj )
	{
		if ( listeners == null )
			listeners = new ArrayList( );
		if ( obj != null && !listeners.contains( obj ) )
			listeners.add( obj );
	}
	/**
	 * Removes a listener. The listener is removed from the list of listeners.
	 * If the item is not in the list, then the request is silently ignored.
	 * <p>
	 * Part of: Notification system.
	 * 
	 * @param obj
	 *            the listener to remove
	 */
	public void removeListener( Listener obj )
	{
		if ( listeners == null )
			return;
		int posn = listeners.indexOf( obj );
		if ( posn != -1 )
			listeners.remove( posn );
	}
	/**
	 * Removes all listeners on this element.
	 * <p>
	 * Part of: Notification system.