Comment 1 for bug 217968

I also have this problem when I connect the monitor and the laptop is suspended.

I have the panels on my left external screen, so when I wake up the computer my panels are out of sight :(

The workaround is to always resume with both screens connected, use gnome-display-properties to switch off the external screen.

I suggest that when a monitor "has gone missing" Ubuntu should resize the virtual desktop to fit the only monitor available.