So, here's how you fix that:
In Firefox type this as the address:
And then click "Yes, I want to void my warranty" or whatever.
Then find the following settings:
You can set it to false by double clicking on it.
Then find, right below it,
and double click that.
Now if you really _want_ to highlight the whole bar you can double click on it, but it won't auto-highlight the location bar by default when you tab away and tab back. Yay.