Upstream Openbve 1.2.1.2 contains a workaround that ignores the first (erronous) mouse movement event following a screen geometry change (eg. windowed to fullscreen or vis-versa).
Ideally libSDL should be fixed to update its conversion matrix one frame sooner to avoid continuing to pass the single mismatched mouse movement event.
Upstream Openbve 1.2.1.2 contains a workaround that ignores the first (erronous) mouse movement event following a screen geometry change (eg. windowed to fullscreen or vis-versa).
Ideally libSDL should be fixed to update its conversion matrix one frame sooner to avoid continuing to pass the single mismatched mouse movement event.