Just to briefly go back here for a moment ... ^^^ ... because it seems to be a point of relative confusion for some.I somehow thought this can be used with a touch-screen exclusively.
Afaik, any software (with no exceptions that I'm personally aware of anyway, mmv) that runs on OSX or Windows can be operated with a mouse (well... command line type apps excluded of course ) so I made that logical assumption immediately when he said he was using a tablet PC, that his finger was just acting as the mouse... or fingers plural for multi-touch.
But sure, if that tablet had been a proprietary controller thing that actually came with the mixer, something running some other OS from it's ROM or something, maybe a different story.