Right mouse buttons stopped working

[John Coppens]

Hi people,

My wife sent me a mail (from her job) that the right mouse button stopped
working. Changing mice doesn't solve the problem, neither does
entering/exiting xfce. Once a program is started, the button _does_ work.

So, it's not impossible to call the application menu by right-clicking
the background (I had removed the menu button in the toolbar).

She can now start programs using Alt-F2 (run menu), but how do I find
out why the right button stopped working?

Thanks,
John