Boxes only uses a tiny fraction of the screen

Applications
1

Synopsis:

I am running Gnome Boxes on a host system with a large FHD monitor. However, the virtual machine only uses a really tiny display, making text on the tty illegible. I maximized the Boxes window, but it makes no difference. Here’s a screenshot of a virtual machine running. Notice almost all of the Boxes window is blank.

Host information: Debian 13 stable, KDE Plasma 6.3.6, Wayland.

Boxes information: 50.0-stable, flatpak

Flatpak version: 1.16.3

Boxes-screenshot
Boxes-screenshot1920×1080 118 KB

2

I figured out the issue:

I had accidentally set my display settings in Plasma to 105% scaling. That was small enough for me not to notice, but big enough to trigger this bug.