OpenGL bug with scissor rectangles

[BillyDM]

There seems to be a bug in wgpu when setting scissoring rectangles with the OpenGL backend, causing rendering issues. Further investigation is needed.

I have only tested the OpenGL backend on my Arch Linux system running on an AMD RX570 graphics card with the KDE desktop environment (I get the same problem in both Wayland and X11).

(I'm creating this issue for future reference.)