> In my (admittedly outdated) experience, alt-tabbing out of fullscreen OpenGL apps has > always been a bit fucky. It may be more related to video drivers than anything.
Well practically the only OpenGL game I have currently installed is the DOOM (2016) [demo], and with that I can alt-tab to other windows. The funky part here for me is that DOOM also switches the screen resolution while it is running, and so alt-tabbing to other windows messes things up because the resolution is still changed. It sets it back to the original resolution when you exit the game though.