It's not possible to use "show pointer" on 7 inch screens. The second pointer on the left,which normally should stimulate the alt-Key isn't visible. The pointer is hidden behind the left toolbar! I use Photoshop Touch on a Nexus 7¹³ and I it's an awesome Software and it would became even more awesome if this issue get fixed ;-)
I can repro this on my Nexus 7 2013 as well; I can see the "hold" icon in the lower left but it's a bit obscured by the "redo" icon. I can still tap it to complete the operation though, even if I can redo.
I was also able to get around it by tapping the full screen icon, 1st icon from the upper right. This enables full view of the "hold" icon.