Window borderer is not rendered doing the animation that plays when a window goes fullscreen

[alba4k]

This was briefly discussed here: #11490 (comment). I know this might not be trivial (I suppose the "border state" updates as soon as the animation starts, both when entering and exiting fs), but will still leave this here as it should not be considered expected/correct/intended behavior.

The window border disappears at the beginning of the animation of a window going fullscreen, instead of being shown throughout the animation. The behavior that can be seen while a window exits fullscreen mode is correct (border appearing immediately).

This leads to a weird borderless window being rendered during the animation, which is especially noticeable when using slow animations or custom gestures (added by #11490).

2025-08-25.00-16-00.mp4