When attempting to link in split screen I evoke Hookmark on an item and for a brief moment the context window shows the selection and then changes to no linkable items. It’s not app dependent. I obviously don’t use split often or would have noticed this. I can sort of understand why, I just expected the 2 windows to be totally separate entities.
BTW: MBP, M1, Ventura, using stage manager, Hookmark Version 6.0.1 (5788; Integration v. 316)