When selecting borderlands in the latest Crossover 16.0.0 Linux build MouseWarpOverride is set to "force" by default. This causes the mouse to be stuck in the center of the application for me unable to move (keyboard input still works).
Simply setting this value to "none" allows the mouse to work as expected for me. Perhaps this value shouldn't be set by default any longer?
If you have the same problem, try to edit MouseWarpOverride through regedit.
In Crossover, Go to Menu/Programs/ and choose "Run Command".
Choose the bottle and type "regedit".
Go to: HKEY_CURRENT_USER/Software/Wine/DirectInput
find MouseWarpOverride, and change "force" to "none".