[Selecting clone tool source with a tablet]

It's an intuos pro medium (PTH-651) and I am indeed holding alt down, which works with the mouse but as soon as the pen goes near the tablet it turns from the cross to the circle so I can clone but not select source. 

[Selecting clone tool source with a tablet]

Pressing Alt results in the cross to select clone source, and I can click it with my mouse, but not the wacom as soon as my pen goes anywhere near that tablet it changes to the circle and wants to do cloning not selecting the clone source.

 

This is driving me nuts, any help appreciated.

 

Thanks,

 

Anthony