Yep the unhide in the quad is for objects not sub-objects. I found this bass ackwards too. I ended up adding "unhide all (sub-object)" to the quad menu using the Main Menu > Customize > Customize UI > Quad menu tab. You'll notice there are a bunch of unhide entries, even two almost identical entries that both say "unhide…
#1 Im having an issue with unhiding the geo I hid to get at the mouth bag I put on this model. I used the "Hide unselected" in the upper right rather than the other one, which didnt work, which is probobly why all my google searches where unsuccessfull. unhide all or unselected doesnt work. I just want to see my polys…
Use the 'unhide all' in the poly sub-object rollout. The unhide all in the quad menu is for objects not polys. For zbrush to use groups you need to do that in the UVW coords, move each set of polys you want in different groups out of 0-1 uv space. So one set goes in 0-2, then 0-3, and so on.
If you absolutely cannot find a way, try exporting to obj and back with minimal information (no normals/etc) that usually clears any hard to correct state issues.