Bug 146761 All structure properties change can't be restore
Steps to reproduce: 1.New a report, extends lib.table 2.Add a structure property(such as filter, column binding...) on table 3.Choose the table, click "Restore Property" Expected result: Local propery is removed Actual result: Local property can't be removed so that "Restore Property" is always enabled
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/SimpleGroupElementHandle.java
}
			}
		}
		catch ( SemanticException e )
		{
			stack.rollback( );
			throw e;
		}
		stack.commit( );
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.api.GroupElementHandle#isExtendedElements()
	 */
	public boolean isExtendedElements( )
	{
		if ( elements.isEmpty( ) )
			return false;
		for ( Iterator iter = elements.iterator( ); iter.hasNext( ); )
		{
			Object next = iter.next( );
			if ( !( next instanceof DesignElementHandle ) )
				return false;
			DesignElementHandle designHandle = (DesignElementHandle) next;
			if ( designHandle.getExtends( ) == null )
				return false;
		}
		
		return true;