Bug 155943 "Restore Properties" is always enabled for extended chart
Steps to reproduce: 1.New a report, includes a library, extends lib.chart 2.Choose the chart Expected result: "Restore Properties" is disabled untill set/change any local properties for the chart Actual result: "Restore Properties" is always enabled
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/writer/ModuleWriter.java
* @param obj
	 *            the grid item or table item
	 * @param slot
	 *            the columns slot
	 */
	private void writeColumns( DesignElement obj, int slot )
	{
		assert obj instanceof GridItem || obj instanceof TableItem;
		assert slot == GridItem.COLUMN_SLOT || slot == TableItem.COLUMN_SLOT;
		
		
		
		boolean revert = true;
		if ( revert )
		{
			writeContents( obj, slot, null );
			return;
		}
		List list = obj.getSlot( slot ).getContents( );
		if ( list.isEmpty( ) )
			return;
		
		boolean needWrite = false;
		Iterator iter = list.iterator( );
		while ( iter.hasNext( ) && !needWrite )
		{
			DesignElement column = (DesignElement) iter.next( );
			List propDefns = column.getPropertyDefns( );
			Iterator iterDefn = propDefns.iterator( );
			while ( iterDefn.hasNext( ) && !needWrite )