Cannot import encfs folder into cryptkeeper

I tried to set up an encrypted folder on Ubuntu 16.04 Xenial with Gnome desktop. I know that encfs is not considered especially safe anymore, I decided to use it for my purpose anyway. Encrypting a folder with

encfs /home/xy/.hidden /home/xy/unhidden

worked fine. To add a little more usability to that, I installed cryptkeeper and started it. When I now try to import the newly created encfs-folder, I can see it in the file selection dialog, after enabling hidden files, but I can't seem to figure out how to actually select it for import. There's no "OK" or "Select" button when I highlight it. There's no difference if the folder is mounted or not. Is that a known bug of this combination or am I too dumb to select a folder?

Edit: Screenshot of dialog included.

In english: "Ordner anlegen" means "Create folder", "Abbrechen" is "Cancel" and "Vor" seems to be "Prev." in this context.