I would like to get a right click shortcut to add a single photo that is open in Preview mode to the currently select collection.
I find it awkward to be scrolling through photos one at a time and have to go back to the contact sheet to add a photo to a collection.
Thanks for your suggestion, Simon. If you'd like to see Simon's feature suggestion, please upvote his post and leave a comment on how you would use it. Thanks!
You can now use the keyboard shortcut command/control B to add selected photos to the current selected collection.