minimized windows gone missing in KDE

[Josef Lowder]

On my KDE system, when I minimized windows, their titles always used
to appear in the panel (task bar) and I could just click on those
titles to reopen them.  But recently something happened so that no
miminized windows appear in the task bar.  How can I restore that
function?

I have tried 'configure panel' and resetting every option in there to
the default settings; and I've tried shutting down and restarting the
system, but nothing I've tried so far has worked.

When I do 'ps -ef' the minimized applications still appear in the list
of running processes, but I can find no way to reopen those running
applications.