Mouse stops working when touching top edge of the screen in fullscreen

[dreamer]

This is not a bug in steam-dos, this issue exists to track down which software is responsible and track the fix.

This is annoying issue, that I experience in practically any DOSBox game (when using steam-dos or just native dosbox through Steam) and also in some other games (OpenTTD - only when started through Steam).

To reproduce this bug:

Start a game using dosbox with following options:

[sdl]
fullscreen=true
fullresolution=desktop
output=opengl

(these are defaults for steam-dos)

After the game starts, keep moving mouse towards top-left corner of the screen. At some point cursor will "bounce back" and top side of the screen won't be reachable any more. In FPS games (e.g. Doom) the mouse will simply stop working until you move the mouse significantly towards lower edge of the screen.

This makes DOS games rather unplayable (in action games your controls occasionally don't work, in strategy games parts of UI are unreachable).

Initially I thought it was a DOSBox bug or perhaps SDL bug (because I could reproduce it in OpenTTD), but it doesn't seem to be the case.

I can reproduce this bug in:

• Steam on Gnome 3.30.2 shipped with Fedora 29 (using Xorg)
• Steam on Gnome 3.30.2 shipped with Fedora 29 (using Wayland, although it's harder to reproduce)

I tried and cannot reproduce it in:

• Running the same games outside of Steam on Gnome
• Steam on Cinnamon (so that rules out a bug in mutter, I guess)
• Steam on KDE (even when I explicitly enabled KDE expose in top-left corner)

Enabling/disabling Steam Overlay does not affect the outcome.

[dreamer]

… aaand the problem fixed itself after upgrading to Gnome 3.32.