After a popup from "..." context menu is opened and closed again on /flags and /configs the page is unresponsive

[mwhnrt]

Steps to reproduce:

• navigate to /flags or /configs in an Abby project
• if you don't have a flag/config created already, create one
• on that flag/config click the "..." menu on the left and choose e.g. "Edit Name"
• let the popup appear and close it again
• try to click anything on the page

Expected behaviour: Every just works as before.

Current behaviour: Nothing is clickable

Hint: I would think that the backdrop of the popup has not been removed correctly and prevents the clicks from going through.

[mwhnrt]

This duplicates #117