make it go away! Rated 5 out of 5 stars
Go back to the way it was:
Enter about:config in the address bar.
Ignore warning & click button to carry on.
In the filter bar, enter browser.urlbar
Doubleclick browser.urlbar.matchOnlyTyped to change it to True
Doubleclick browser.urlbar.maxRichResults and you get a box pop up. Enter 0
You are done!