Strange mouse/cursor behaviour in fullscreen apps

[Tipcat-98]

This started around the time when #448 and related commits were added.

In one game, V Rising.
The cursor is offset from it's actionable position.
As seen in the screenshot the option box is highlighted when the cursor is moderately to the left of it.
This only happens in "Exclusive Fullscreen" mode, where in "Windowed" it works fine.

https://media.discordapp.net/attachments/633653387723931659/1240331053198217216/IMG_2177.jpg?ex=66462bcf&is=6644da4f&hm=6ed2bf35c8961e1520daea2d50bf350bf7d8d1ce1820a1a5d1f401db045a7ece&=&format=webp&width=895&height=671

In another game, World of Warcraft.
The cursor position matches where it actually is but you cannot move it to the very right of the screen.
As seen in the screenshot, I cannot move it further to the right.
This only happens in "Fullscreen (window)" mode, in "Windowed" mode it is fine.

https://media.discordapp.net/attachments/633653387723931659/1240331052250173602/IMG_2178.jpg?ex=66462bcf&is=6644da4f&hm=785a6fbe5937073b46aead7a76c4a7cb90b7764613c7704ee8ef30cd4b1d0ca0&=&format=webp&width=895&height=671

I have two 1920x1080 monitors and I'm on Nvidia.

System Info:
Cosmic: Updated to latest git as of today
OS: Pop!_OS 22.04 LTS x86_64
Kernel: 6.8.0-76060800daily20240311-g
DE: GNOME 42.5
CPU: Intel i7-6700 (8) @ 4.000GHz
GPU: NVIDIA GeForce RTX 2060 Rev. A
GPU Driver: 550.67
Memory: 32024MiB

[Tipcat-98]

I can't really confirm if this only happens with xwayland apps.

Sidenote (might be related, not sure):
I tried native wayland terraria and it does exhibit the same instability with nvidia as my other issue - #419.

I'll rename to say fullscreen apps.