Windows goes nuts when pen not on tablet (

I'm using an Intuos CTH-690 (Intuos Medium) in Windows 10. Have tried various Wacom drivers (currently on latest 6.2.22-g)

All works fine when the pen is being used on the tablet, but when you take the pen off the tablet surface, Windows goes crazy. Contextual menus pop up, windows close, mouse curser jumps around, icons get selected, etc...

Basically, if I put the pen on my desk, sip coffee, scratch my face or use the keyboard while holding the intuos pen I step closer into insanity.