If you want to restore the old search bar behavier in FF 34, Follow These steps :-
1- Open about.config Page
2- Search for:- browser.search.showOneOffButtons
3- Change value from "True" , to, "False"
4- Restart FF 34 ,
Now, you can reuse "Second Search" like before .
What I really wish to be supported in Second Search, is the ability to keep the menu opened after clicking on a search engine, So we can search with multiple engines, without needing of reopening the search engines list ... Cheers