What's the keyboard shortcut to open the "new menu" (PanelUI) in Firefox 29?

I am referring to this button:

enter image description here

(called variously as "new menu" or PanelUI, thanks ciastek!)

Is this basically a mouse-only button and menu, or is there some secret way of using it with the keyboard?


Solution 1:

If you put the searchbar in the menu, you can use Ctrl-E or Ctrl-K to open it. That's the best I've found so far.