Comment 16 for bug 765819

Changing the Firefox layout would interfere with muscle memory, just to accomodate an Ubuntu bug. And doing so wouldn't solve the problem for Chromium, Epiphany, Midori, or Opera users.

I personally like GNOME Shell's solution of making the upper-left corner the trigger. It doesn't seem as intuitive here since the launcher comes out of the left side, but it's a lot harder to accidentally trigger.