I’m looking at this on beta 1.5.0.9, but I have the same issue on the latest release version (1.2.5)
I have a gap in my search menu. I presume this should be for searching comments / footnotes, but I can’t seem to get a search on this category to yield any results 
It looks like you may have just accidentally cleared the “Label” name in Project > Meta-Data Settings. It’s editable and the name you provide will be the one used throughout the interface.
There is no separate project search category for searching comments/footnotes; they’re to be included in the regular “Text” search, since that’s what they are. You can however use the Find by Formatting tool to search just comments or footnotes for specific text.
Thanks Jen! That’s fixed it!
So, worth pointing out, I guess, that if you clear the custom name for either “Label” or “Status” the term in the Search menu doesn’t revert to the default in the same way that the tags do in the Inspector.
Noted! 