Hover and focus effects of Wayland titlebar are broken for lazy redraw apps

[ell1e]

Hover and focus effects of Wayland titlebar are broken for lazy redraw apps. It seems like the titlebar just expects that whenever it changes visible items, surely the app will refresh and redraw in the next milliseconds no matter what. This seems conceptually wrong since while SDL2's event poll mechanism isn't ideal for lazy redraw, I don't think anything in the documentation declares that lazy redraw is disallowed. Therefore, the titlebar simply cannot assume the app will redraw it unconditionally in an always timely manner without any notification to do so.

Problem seen on SDL2 version: SDL2-2.26.0-1.fc36

Seen on Linux distribution: Fedora 36

Seen on desktop: GNOME 3 Wayland