Found that when trying to use the Kate editor, the search-and-replace, document list, or any other tool bar enabled in the plugins, won't open on click. If you go to the menus and open them there, they work. But the mouse has no effect other than changing the tab color to show it's selected.

There are no errors reported in the journal, nor anything when run from a terminal. Everything else is working, menus, buttons, settings dialogs and tabs. Just not the tool-view tabs.

Tried re-installing, removing all the settings from ~/.config, turning on one plugin at a time, nothing makes a difference. Searched the web and KDE's bugtracker, nothing so far reported or mentioned about it.

So... I'm out of ideas.