Comment 7 for bug 891648

I've been frustrated a number of times expecting tab completion to work in the search field.

The CUA-inspired scheme we once discussed for GNOME was that there was a sort of hierarchy of modifier key bindings. I forget to what extent we went with it. Here are a few examples:

Session level - Ctrl+Alt+key
Ctrl+Alt+Backspace - kill the X server
Ctrl+Alt+Delete - log out, shutdown, etc., like Windows.
Ctrl+Alt+L - lock screen
Ctrl+Alt+D - show desktop

Window level - Alt+key
Alt+Tab - switch between windows
Alt+F4 - close window
Alt+F9 - minimize window

In-window level - Ctrl+key
Ctrl+Tab - switch between tabs
Ctrl+F4 - close tab or child window
Ctrl+F9 - minimize child window or hide tab

This was before the logo key was ubiquitous and commonly mapped to Super, which would take the place of Ctrl+Alt.