Bug 176436 Charts Imported from Libraries do not update when libraries change
During a live presentation of BIRT at EclipseCon, we came across a rather embarassing issue. When charts are included in a library, and imported into a report design from a library, any changes to the library instance of the chart do not reflect in the report itself.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/command/PropertyCommand.java
String label = ModelMessages
				.getMessage( MessageConstants.CHANGE_ITEM_MESSAGE );
		stack.startTrans( label );
		makeLocalCompositeValue( ref );
		MemberRecord record = new MemberRecord( module, element, ref, value );
		record.setEventTarget( getEventTarget( ref.getPropDefn( ) ) );
		stack.execute( record );
		Structure structure = ref.getStructure( module, element );
		List semanticList = structure.validate( module, element );
		if ( semanticList.size( ) > 0 )
		{
			stack.rollback( );
			throw (SemanticException) semanticList.get( 0 );
		}
		stack.commit( );
	}
	/**
	 * Check operation is allowed or not. Now if element is css style instance ,
	 * forbidden its operation.
	 * 
	 */
	private void checkAllowedOperation( )
	{
		
		if ( element != null && element instanceof CssStyle )
			throw new IllegalOperationException(
					CssException.DESIGN_EXCEPTION_READONLY );
	}
}