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/Module.java
* Removes one validation listener. If the listener not registered, then the
	 * request is silently ignored.
	 * 
	 * @param listener
	 *            the validation listener to remove
	 * @return <code>true</code> if <code>listener</code> is sucessfully
	 *         removed. Otherwise <code>false</code>.
	 * 
	 */
	public boolean removeValidationListener( IValidationListener listener )
	{
		if ( validationListeners == null )
			return false;
		return validationListeners.remove( listener );
	}
	/**
	 * Broadcasts the validation event to validation listeners.
	 * 
	 * @param element
	 *            the validated element
	 * @param event
	 *            the validation event
	 */
	public void broadcastValidationEvent( DesignElement element,
			ValidationEvent event )
	{
		if ( validationListeners != null )
		{
			Iterator iter = validationListeners.iterator( );
			while ( iter.hasNext( ) )