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
* 
	 * @see org.eclipse.birt.report.model.elements.ElementVisitor#visitScriptDataSource(org.eclipse.birt.report.model.elements.ScriptDataSource)
	 */
	public void visitScriptDataSource( ScriptDataSource obj )
	{
		writer.startElement( DesignSchemaConstants.SCRIPT_DATA_SOURCE_TAG );
		super.visitScriptDataSource( obj );
		property( obj, ScriptDataSource.OPEN_METHOD );
		property( obj, ScriptDataSource.CLOSE_METHOD );
		writer.endElement( );
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.elements.ElementVisitor#visitExtendedDataSource(org.eclipse.birt.report.model.elements.ExtendedDataSource)
	 */
	public void visitOdaDataSource( OdaDataSource obj )
	{
		writer.startElement( DesignSchemaConstants.ODA_DATA_SOURCE_TAG );
		attribute( obj, DesignSchemaConstants.EXTENSION_ID_ATTRIB,
				OdaDataSource.EXTENSION_ID_PROP );
		super.visitOdaDataSource( obj );
		writeOdaDesignerState( obj, OdaDataSource.DESIGNER_STATE_PROP );
		List properties = (List) obj.getLocalProperty( getModule( ),
				OdaDataSource.PRIVATE_DRIVER_PROPERTIES_PROP );
		writeExtendedProperties( properties,
				OdaDataSource.PRIVATE_DRIVER_PROPERTIES_PROP );
		writeOdaExtensionProperties( obj, OdaDataSource.EXTENSION_ID_PROP );
		writer.endElement( );
	}