i have no real use for the popup space bar menu, but i would like to re map it to another key such as ` for example. i know i can do this with sharpkeys, but that does a global change.
is there a program that can re map only in certain programs(zbrush only)?
Don’t forget that Spacebar is also used with Clip Brushes, Selection Brushes and Mask Brushes for moving.
oh forgot about that …D:
but i found a solution with autohotkey 
You can actually assign any hotkey you want to the Preferences>Interface>Misc>Quick Menu button but that won’t remove the spacebar behaviour.