I've tried it both in the tray and with the notifier separately on the panel, but when I put a DVD in the drive it displays in the device notifier menu but won't launch from there. I can click on open with file manager, open with dragonplayer/kaffeine, or open with k3b, and all that happens is the menu disappears. I can open them from the app in question, but not from the device notifier. This applies to data DVDs and video DVDs, to some flash sticks, but not to audio CDs. Can anyone tell me what's going on?

Please enable debug output using "kdebugdialog" ( all areas ) then logout and back in again, and try. If it doesn't work, check in ~/.xsession-errors for any output explaining why it didn't work.

Erp... turns out it was my fault. This was on a new box that I just installed, and somehow I failed to add my user to the necessary groups. The reason I didn't think to check it wa that the user was able to open those media by other menas, which was very odd indeed.