This conversation has been merged. Please reference the main conversation: Lightroom SDK: stack ops
At present, a plugin can only set the stack position when adding a photo to the catalog. I would also like to be able to alter stack-position after the fact, for a variety of reasons, including plugin synchronization of proprietary xmp-like info, i.e. if plugin has saved proprietary xmp-like file, which includes stack position, that info can be applied to the catalog by plugin, including stack-position.