Search Bar Not Working...

In Firefox 31.8.0 the search bar does not work (it lets me choose a 
search engine, accepts search text and supplies suggestions for the 
text, but it does not go to the search site). If I enter text instead of 
a url in the location space, it searches as if it were the old search 
bar. I created a new profile for FF and the old search bar works.

Using the latest FF in Windows 7, 8.1, and Linux the old search bar 
function still works.

I wonder if there might be a config variable that toggles this behavior. 
Has anyone looked into this and found out what triggers this "improved" 
behavior of the search bar?

Martin Rosenfeld