I've tried rotating my part model with the mmb (middle mouse button) and it won't work. At best, it zooms in and out. I'm working with a Microsoft mouse, identical to my colleagues mouse, which seems to work (rotate) on his workstation. The mouse settings are identical as well. Is there a checkbox within Solidworks that is deactivated somehow? I've even tried plugging in another mouse, but get the same result.

I can still rotate with the arrow keys, but it is definitely not as convenient. Any help would be appreciated.