Bug 176450 Support link to CSS Feature(Model Part)
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/command/PropertyCommand.java
*             if any semantic exception is thrown.
	 */
	private void clearRefTemplateParameterProp( ElementPropertyDefn prop,
			Object value ) throws SemanticException
	{
		assert prop != null;
		assert IDesignElementModel.REF_TEMPLATE_PARAMETER_PROP.equals( prop
				.getName( ) );
		ActivityStack stack = module.getActivityStack( );
		stack.startTrans( );
		try
		{
			ElementRefValue templateParam = (ElementRefValue) element
					.getProperty( module, prop );
			TemplateParameterDefinition definition = (TemplateParameterDefinition) templateParam
					.getElement( );
			doSetProperty( prop, value );
			if ( definition != null && !definition.hasReferences( ) )
			{
				ContentCommand cmd = new ContentCommand( definition.getRoot( ),
						definition.getContainerInfo( ) );
				cmd.remove( definition );
			}
		}
		catch ( SemanticException e )
		{
			stack.rollback( );
			throw e;
		}
		stack.commit( );