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
if ( obj.getExtendsElement( ) == null )
			return;
		writer
				.conditionalStartElement( DesignSchemaConstants.OVERRIDDEN_VALUES_TAG );
		Iterator iter = new ContentIterator( obj );
		while ( iter.hasNext( ) ) 
		{
			DesignElement virtualElement = (DesignElement) iter.next( );
			writer
					.conditionalStartElement( DesignSchemaConstants.REF_ENTRY_TAG );
			long baseId = virtualElement.getBaseId( );
			writer.attribute( DesignSchemaConstants.BASE_ID_ATTRIB, new Long(
					baseId ).toString( ) );
			writer.attribute( DesignSchemaConstants.NAME_ATTRIB, virtualElement
					.getName( ) );
			writer.attribute( DesignSchemaConstants.ID_ATTRIB, new Long(
					virtualElement.getID( ) ).toString( ) );
			if ( !virtualElement.hasLocalPropertyValues( )
					&& virtualElement.getStyle( ) == null )
			{
				writer.endElement( );
				continue;
			}
			assert virtualElement.getExtendsElement( ) == null;
			List propDefns = null;
			if ( virtualElement instanceof ExtendedItem )
			{
				propDefns = ( (ExtendedItem) virtualElement ).getExtDefn( )
						.getProperties( );
			}