For some reason my mouse pointer has gone missing in Stellarium, and I have no way of navigating!

Moving the mouse around allows me to 'highlight' selections on the toolbars on the bottom and left hand side of screen,
and I can get the configuration popup to display but can not highlight or select anything on the popup.
My MS Intellimouse Explorer 3.0 works perfectly in every other application.
I've reset the mouse to it's default settings, and I'm not using any weird pointer or anything!
I've tried re-installing Stellarium V11, and have even gone back to V10.6.1 but all to no avail.
Are there any settings I can tweak to get it back?
Cheers

Chris