Comment # 1 on bug 1078480 from Wolfgang Bauer

Works fine here.

Are you trying to modify the default profile?

Probably related to https://bugs.kde.org/show_bug.cgi?id=369328 then.
I.e. it will create a new profile to save the settings, but only actually uses
that new profile on next start.

If that's the case, you should notice that there is a new "Profile 1" used
after restart.
And further changes to the new profile should then be applied immediately.