Dell E6320 Touchpad Buttons

I re-installed the OS (Windows 7) on my Dell Latitude E6320 recently. After re-installing all the drivers I cannot get the top middle touchpad button to work. Previously this button worked fine as the middle mouse button. I cannot find anything in settings to enable this button. Is there a specific trick to get this to work? The other two top buttons work fine (left and right click). I am not referring to the trackstick nub.