if ( !containsListingElement( toAdd ) )
if ( !( toAdd instanceof ListingElement ) && !( ModelUtil.containElement( toAdd, ReportDesignConstants.LISTING_ITEM ) ) )
	public List validateForAdding( Module module, DesignElement element,			int slotId, DesignElement toAdd )	{		if ( !containsListingElement( toAdd ) )			return Collections.EMPTY_LIST;		return doValidate( module, element, slotId );	}