Can't sort comments

[troelsselch]

In FireFox 53.0.3 (64-bit) on Ubuntu I cannot change the sort order for comments. When I click the sort menu it opens, but when I click any item it closes the menu and activates/focuses on the comment text area. This only happens on the /r/web_design subreddit.

I can make the comment sorting work by disabling the z-index for ".commentarea .usertext-edit textarea" in the inpspector, however this is not a reasonable workaround for every day use.