display on PC

Hi - I recently updated to the latest version of MuseScore, and now, when I open it, I am getting a peculiar display setting.

First, if I open a score I'm working on, I am given 2 copies, one on top of the other.

I am used to working vertically, not horizontally - but I seem to get both at present.

Second, the display is far wider than my screen - in fact, it's wider than the 2 screens I am working with. I only want MuseScore on 1 screen! So I can have the other screen to work on email, etc.

How can I fix this, please?

thanks