Double tapping letter Z is working, but not hold letter.the control keys for the tools are:
A--Cursor (Marquee Tool)
R--Reshape Tool
P--Pencil Tool
I--Ibeam Tool
S--Scrub Tool
Z--Zoom Tool
Tap and hold the keys to access that tool temporarily, or tap twice to switch to that tool until you make another switch.
Any pref settings might solve this?