Does the mouse do anything at all?

If you have the 'Compact 2' selected for 'Keyboard Size' at Config -> Misc. 2, then you might indeed find some odd behaviour (camera panning from each default mouse buttons, movement from middle mouse button, et cetera) as this is a rather newly implemented controlling scheme.

To have the old behaviour back, select the 'Full' or 'Compact 1'.


I hope this helps ! !! !
Good luck~