When an XMP (embedded processor) source is added to an ISE project, Project Navigator sets intstyle=ise to specify to XPS that this project has been instantiated in Project Navigator. When this setting is used, XPS does not allow certain fields to be modified to allow correct integration. However, if you delete the XMP source from the ISE project, the intstyle value is not reset to default and user control is not restored for the options controlled by the intstyle=ise setting.