I set up a theme for the grub bootloader and changed the resolution to 1920x1080 with
So far this works fine.
But after I select the OS, a blank "box" pops up in the center and stays for a couple seconds. The box is smaller than the boot menu, so the boot menu is still visible on the sides. The background color of this box is the one I set in
if background_color 99,0,0,0; then clear fi
This box (respectively the background color) also appears briefly before the boot menu is visible, but at that point, it's covering the entire screen.
When I press
c in the boot menu, the same "box" (terminal) also appears with the reduced dimensions.
This is not a big deal, although it is a little bit annoying. So if there is an easy fix for this, I'd like to change it.
PS: If I set
GRUB_GFXMODE=640x480, both boot menu and "box" have the same dimensions
This is a picture of the "box" after selecting OS: