the search field needs a different min size or something, Im always finding myself with this situation where the UI doesnt switch although the search field is too small
yea, the min width for the search panel is way too small - you can squeeze the UI to the point where the buttons are meaningless. Maybe you should open a ticket about it in bugs.kde.org.
ok, made one
https://bugs.kde.org/show_bug.cgi?id=488727