Version:            (using KDE 4.2.2)
Installed from:    Ubuntu Packages

In the "Configure local and remote Printers" page, there appear three buttons at the bottom of each printers' page: "Clean Print Heads", "Print Self Test", and "Print Test Page". When clicking "Print Test Page" the button changes to read "Cancel Print". When the print is done, the button does not change back to read "Print Test Page" but rather stays "Cancel Print" until the user exits System Settings and reopens it.

I did not check the "Clean Print Heads" or "Print Self Test" pages for similar bugs, but they should be checked as well.