Using Ubuntu 12.04. First it came with Unity, then with a zeal of trying other Desktop Environments and I have installed GNOME-shell and no conflicts, works fine. Then I have gone through Lubuntu and Xubuntu as well. But some panel problem started with Lubuntu raised and I have removed Lubuntu DE from my PC.
But that thing got conflicted with my Unity, GNOME and Cinnamon & they are not working. These three are not having only of their Panels. I just see any empty desktop. Currently only KDE and Xfce can run fine with my Ubuntu 12.04. But I want to get back with Unity, GNOME and Cinnamon also.
This is how my desktop look like