I find myself wishing there was a way to perform full project searches on projects not currently open (and/or other than the project where the search is being performed.)
I imagine that actually doing multiple project searches wouldn’t be as tricky as finding a sensible way of presenting the results.
As a workaround on the meantime, Windows search directly from Windows Explorer might be of use. Not so powerful, but comes up with some results for simple cases.
Searching through multiple unopened Scrivener documents is a feature I also would like to see implemented…
It would allow you to look for unused ideas you once poured into scrivenings in projects you were working on. Or it could prevent you from using the same brilliant ideas …