Since the end of the holiday event, tabbing out of SWL frequently causes my mouse cursor to get trapped in the top left of the screen until I tab back to SWL.
At the same time, though I doubt it is related other than ‘came in the same patch,’ after tabbing back into SWL there is a noticeable pause and a visible flicker as the ground textures vanish and then reload. This wasn’t happening before.
This used to happen for me in the past. For me it helped to simply rebind the mouse mode toggle key, which by default is your L-Alt. L-Alt is also involved in tabbing between windows, which is likely why this is happening. The inconsistency in it happening, probably depend on which mouse mode you were in, when you tabbed out of the game.
Either way try bind the mouse mode toggle to something else, it will likely “fix” it for you. I bound mine to clicking the mouse wheel.
Update: For some reason, despite the menu saying that the game was borderless windowed, it was actually fullscreen. I set it to windowed and then back and that seems to have fixed things. Somehow it seems to have changed/reset the setting without the menu updating.
I had that issue with steam since the overlay grabbed it…strangly that fixed it self. Happy I am not plagued by it anymore but I assume other programs can cause the same issue.