sentences:  Now it is part of GNOME Flashback, an official session for GNOME 3 which provides a user experience similar to GNOME 2.In GNOME 3, customizing GNOME Panel is done by pressing the key while right-click on the panel.By default, GNOME Flashback contains two panels (one on the top, and one to its opposite on the bottom) spanning the width of the screen.