1) I put a DVD in the optical drive.
2) Ubuntu detected the DVD and displayed the DVD icon on the dash.
3) I pressed the eject button on the optical drive and the disc was ejected. I pushed in the tray.
4) I opened the terminal and typed the command you suggested.
I restarted Ubuntu and the icon disappeared.
1) I put a DVD in the optical drive.
2) Ubuntu detected the DVD and displayed the DVD icon on the dash.
3) I pressed the eject button on the optical drive and the disc was ejected. I pushed in the tray.
4) I opened the terminal and typed the command you suggested.