For some reason for this widgt the option setPassivePopup is enabled (probably because you can't control it with keyboard anyways). Interestingly, the result is that the popup doesn't hide if you, for example, open the settings dialog. This behaviour is a bug and not consistent with all other popup widgets.

I suppose this fixes also https://bugs.kde.org/show_bug.cgi?id=221301

On the other hand, we could also try to fix that passive popup feature, if it's broken...I don't know.