Comment 39 for bug 334544

Given that we're going to have a single indicator applet in the near future, instead of two, another option for default is Alt+F3, or maybe Alt+F5. It rhymes nicely with the shortcut for opening the main menu. Alt+F* feels like a nice convention going forwards for keyboard shortcuts that relate to the panel (with the unfortunate exception of Alt+F4).

Still not wonderfully discoverable, but I think it would be a hair more discoverable than Super+S given that we basically never use the super key for shortcuts by default (and that no normal user knows that a particular indicator is the Session indicator).