Two Identical stacked Scores open and close simultaneously

Hi Everyone

I've been working on a score. I don't know how but I managed to created a view which is of two Identical stacked Scores. These open and close simultaneously. I can alternate between them and the edits affect both versions.

I want to close one of them but when I do I can only close both.
I've tried closing the app, save as, save copy, docs stacked or side by side, but I always get two scores.

Any tips on how to close one of these.
Purely an issue of taking up screen space

Thanks