What the hell is going on here?
For those of you who have done accessibility testing on a Mac, using FireFox, you’ve likley experienced the confusion and frustration that is FireFox not tabbing to link elements by default.
You see, OSX by default has limited tabbing to text boxes and lists turned on by default.
If you set the Keyboard Preferences to “all controls”, as shown in the screen shot above, then OSX, and thus FireFox, will allow the tabbing to all focusable elements.
For some additional information on this, and where I originally found the solution to this issue, check out this stackoverflow thread.