QEMU 6.2.0 fullscreen problem

Host environment

• Operating system: Ubuntu 22.04
• OS/kernel version: 5.15.0-57-generic
• Architecture: x86_64
• QEMU flavor: qemu-system-x86_64
• QEMU version: 6.2.0 (Debian 1:6.2+dfsg-2ubuntu6.6)
• QEMU command line:

   qemu-system-x86_64 \
    -boot d \
    -cdrom ubuntu-22.04.1-desktop-amd64.iso \
    -m 4096M \
    -machine type=q35,accel=kvm \
    -cpu host \
    -smp 2 \
    -device qxl-vga \
    -display gtk

Emulated/Virtualized environment

• Operating system: Ubuntu 22.04
• Architecture: x86_64

Description of problem

After running the command above, clicking on "Try Ubuntu" and adjusting the guest display resolution in GNOME to the native resolution, pressing ctrl+alt+f yields a "fullscreen" that only covers the QEMU window but not the entire host screen. This is not the case when switching to fullscreen while the boot screen is active or running qemu-system-x86_64 -display gtk,full-screen=on.

The problem also occurs when replacing -device qxl-vga by -device VGA,vgamem_mb=64. The problem however does not occur when using -device virtio-vga instead of -device qxl-vga or -display sdl instead of -display gtk.

Steps to reproduce

1. Run the command above
2. Click "Try Ubuntu"
3. Set guest resolution to native resolution (1920x1200 in my case)
4. Move the window a bit off the corners to observe the effect
5. Press ctrl+alt+f

Additional information

The bug has also been reported here.