Created attachment 7077 dialogue screenshot While testing gtk3 panel, I have -q panel and then restarted it. The dialogue that starts has label missing - screenshot attached.
Thanks for noticing, fixed in a few other places as well: https://git.xfce.org/xfce/xfce4-panel/commit/?id=4bb48b03e9236634acba25d8f07d77c998091ef7
Fix will be released as part of xfce4-panel 4.13.0.