Bug : display several macOs in the same screen

[Florent-Breton]

Hi,
I installed and used macOs with succes on a Linux machine. I changed the resolution of the Mac image and everything works well until I turn off my computer. Indeed, since I restarted my computer, when I launch macOs from Clover, with "Boot macOS from macOS", macOs is launched but in a small size of my screen like in the attached picture.

Do you have an idea about the problem, and idealy a solution?
Thanks