I have my main movie collection, but I also have a separate one with just music based movies in them. I was hoping to be able to copy the entries of the music based one also in the main one, so I know my total movie collection, but still am able to see just all movie based ones.
No worries your story makes perfect sense!
However, it is currently not possible to copy a movie to another collection in your database. It is only possible to move a movie to another database (which indeed will make it so you don’t see the total).
We have this feature request of copying on our radar, however it does give some difficulties if we just build this. Some that come to mind: say you copy a movie to your secondary collection, it will just be a duplicate. If you edit the movie in one of your collections, the same edits will not be present in your other collection, so you’d have to to the edits twice.
Perhaps if you need this, it might be better to use Tags, so you can use the Folder button top left to group by “Tags” and instantly see all your music based once (if you add a “Music” tag to them).
Another alternative that is on our radar is to expand the Statistics screen so you can switch between collections there, and also have an “All Collections” statistics screen. That is also on our ideas list.
Hope that helps a bit, and perhaps tagging is the way to go for you!
(Or use 2 collections… and do the math between the two )