[CLIENT] Unable to add Runes

The OSX client (6.21.16_10_13_21_40) does not allow me to add Runes.

1. Log-in
2. View/Edit profile
3. Click 'Runes'
4. Add a Mark (or any type) rune does not work.

Removing a Mark (or any type) Rune (Right mouseclick) and re-adding it also does not work.

Tried logging out/in to see if it solves the issue, but is doesn't. Is it a bug, or is it a feature? ;)