SOLVED was Re: Notifications changed in LXDE under wheezy
I solved the problem by rebooting! What I suspect was happening was that I had right-clicked on the desktop, and said restart for openbox, which when it did my desktop looked the same, but obviously it wasn't the same as I didn't get the openbox menu when right-clicking on the desktop. I don't know what DE I'd got into as I have cinnamon and MATE installed on this box, along with Gnome3 and XFCE, and the aforementioned LXDE.
So the problem is now solved,thanks folks.