Discovered in the course of discussing issue #418.
Right-clicking an editor tab, and clicking "open containing folder", instead of bringing up a file manager brings up gedit (which I presume is the default graphical editor configured somewhere) with the file in question.
Problem found on Debian (Testing), under Gnome, Gnome Shell version 3.22.
Yep. It tries to open the folder and select the file, but it seems to fail. :(
Fixed in rev 11138.