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The mouse in menus and in game moves like... a joystick or a gamepad that is not centred. Starts sliding to the left a bit. I have no gamepads or such plugged in.
Not a lot but enough to annoy you when you wanna build units and it just... I can't find any mods that help. And I'm using dxwnd to play windowed. No options in dxwnd help with the mouse...