Invalid language tag error when changing realm localization settings

Area

admin/ui

Describe the bug

Hi,

When I select a realm from the drop down list that is not the master realm, and then go to Realm Settings and click on the Localization tab, the following error message appears:

Invalid language tag: ""
Press here to refresh and continue

This doesn’t happen for the master realm, only for other realms.

Regards, Rik

Version

20.0.1

Expected behavior

The realm tab opens similar to when the tab is opened for the master realm.

Actual behavior

The following error is displayed:

Invalid language tag: ""
Press here to refresh and continue

How to Reproduce?

Select non-master realm Go to Realm Settings Click the Localization tab

Anything else?

If I create a new realm, I can not reproduce the issue. I can only reproduce it for an existing non-master realm. The realm was created on an older version of keycloak (I believe 15 or even older).

[edewit]

ahh, I see what is going on, there is a call where the locale is "" creating a fix now

[bilias]

I’m also having this on 20.0.1 on all realms, including master.

Maybe it has to do with a custom theme?