I recently upgraded my system to GNOME 3. In previous versions of GNOME, the key combination Ctrl+Alt+D would hide all open windows and show the Desktop. This shortcut was eliminated from GNOME 3 along with the concept of a Desktop. The Desktop metaphor does, however, exist in GNOME 3 "fallback mode" (which I am using).
I would like to reinstate the Ctrl+Alt+D keyboard shortcut. I know at least two ways of creating key combinations in GNOME. One is through System Settings > Keyboard > Shortcuts, and the other is through
gconf-editor > apps > metacity. From either of these environments, I can pair a command with the key combination Ctrl+Alt+D. The problem is that I don't know what command will trigger a "Show Desktop" event. Could someone enlighten me?