Bug 136241 [regression]Preview template in web viewer and pdf didn't get correct effect.
Description: Preview template items in web viewer and pdf didn't get correct effect. Steps to reproduce: 1. Create template items. 2. Preview in Web Viewer and pdf. Expected result: Same effect as in html. Actual result: In web viewer, see only blank box. In pdf, blank page.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
* pointer to the target element itself.
	 * 
	 * @param oldRef
	 *            the old reference, if any
	 * @param newRef
	 *            the new reference, if any
	 * @param prop
	 *            definition of the property
	 */
	protected void updateReference( ElementRefValue oldRef,
			ElementRefValue newRef, ElementPropertyDefn prop )
	{
		ReferenceableElement target;
		
		
		if ( oldRef != null )
		{
			target = oldRef.getTargetElement( );
			if ( target != null )
				target.dropClient( this );
		}
		
		
		
		if ( newRef != null )
		{
			target = newRef.getTargetElement( );
			if ( target != null )
				target.addClient( this, prop.getName( ) );
		}