Mouse thumb buttons are not the same on linux in the glx and sdl versions
The graphical keybind menu reports the down thumb key in the glx version as MOUSE6 and the up thumb key as MOUSE7. The graphical keybind menu reports the down thumb key in the sdl version as MOUSE4 and the up thumb key as MOUSE5.
As a result, binds stop working when you switch between glx and sdl versions until you rebind the keys.