Comment 4 for bug 885691

It's not in gnome-panel.css, It's caused by gtk engine. PanelWidget affects the main panel background. As we see, in Ambiance it's background image is a gradient, but the panel uses 'gtk-gradient to' for whole background, and 'gtk-gradient from' for 1 px line at the top. Just the theme engine doesn't do a gradient there and we cannot modify it by css.

I've even applied the hope theme (which has gradiented panel on the Author's screens from Fedora) and mine panel in Ubuntu 11.10 was flat.