Not Mr Flibble Jul 12 @ 5:33pm
[Linux] [Bugs] Problems with edge-flip, multi-monitor
In game, the view direction sometimes jumps when looking around or trying to manipulate an object. In the menus, the pointer can leave the game window unexpectedly ‒ rather than using the actual pointer position and translating that into internal co-ordinates, the engine appears to be maintaining its own pointer position. (The problems affect Overture identically.)

It may be that all that's needed is pointer grab.