Silly me.

I selected Yes for the "No Title Bar and Frame" option in Special Application Settings. Now I want to change it back. How do I access the Special Application Settings menu without a Title Bar to right-click?

Btw, I tried removing the title bar because I thought it might fix the way Chromium integrated with KDE. Guess I was wrong. Does anyone know how to do this?

Thanks.

there should be a windows setting entry for Chromium in systemsettings -> window behavior -> window rules

Just for the record, I found (rather by accident) that a keyboard short cut exists - press Alt+F3 whilst your programme is running and you will be given the kde window/applications settings again where you can reset your window behaviour.