This has happened to me multiple times over my entire D2 history, but twice in the past week so I'm only posting it now. Suddenly, my mouse will stop working in-game, i.e. unable to look around, shoot, ADS, melee (my mouse 3), while my keyboard controls will stay completely functional. When I press F1 (equip menu), I am able to move my mouse around but am unable to left/right click (equip weapons/armor), hence I am unable to even exit to desktop without alt+f4. If I alt+tab when this happens, my mouse will stay completely functional in the desktop so I doubt this is related to my setup. Plugging out the mouse and plugging it back in does not fix the problem either. The only solution, if only temporarily, is restarting the game, which is annoying, to say the least. I'm not sure if the trigger is me pressing a certain sequence of keys, or pressing too many keys at once, as I'm often in a try-hard activity when this happens (raid, nightfall, gambit).