[dev] Lock mouse focus on window

Is there a way to manually lock mouse focus on a window? I'm running a
game in wine and the mouse leaves the window once I get to the edge.
Since the game is an FPS this isn't really acceptable. Even if I
fullscreen the app the mouse just stops when it gets to the window,
which doesn't really work out. Is there a way I can lock the mouse in
the window so I get the correct behaviour?

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Samuel Baldwin - logik.li