working Rated 2 out of 5 stars
It basically just adds the search. No highlighting of the tab.
Just figured out that the disappearing app tap is a firefox bug. It deletes the tab when the option "clear recent history" when closing Firefox is on.
If you don't want to switch off that option you can NOT use the add-on "app-tab-initializer", because the app tabs will dublicate at the startup.
I finally had success with this add-on:
and this settings:
(Firefox 9 will solve this hopefully..)