I guess I could say the primary purpose of the addressbar is to go to addresses, whereas the primary purpose of search bar is to search for information.

The simplest methods are to use the Search bar that by default is to the right of the addressbar, or the search option on the default homepage.

1. Use popular search suggestions in the Firefox Search bar
2. Also see Address bar autocomplete suggestions in Firefox

The pref mentioned by you, and the second article browser.urlbar.autofill does not change the address bar to behave as the searchbar.

Thanks John! But the reason I want to search using the address bar is that when you open a new tab (which is a blank page), the default focus of the cursor is the address bar. So instead of pressing Cmd+K to switch to the search bar, start typing the stuff I want to search right in the addr bar is much a breeze!

See if this article helps. https://support.mozilla.org/en-US/kb/search-web-address-bar

I missed an important point that you made. You are saying you pressed enter after entering the search term fire

That should result in the address bar using the default search engine (or whatever is set in the Search bar). Something is going wrong.

Maybe you have been changing other things or have some addon causing this problem. First of all try in Firefox's safe mode by for instance holding the shift key as you use the Firefox start icon, or by restarting with addons disabled

• See Diagnose Firefox issues using Troubleshoot Mode

Secondly if that does not help then try creating and testing with a new additional profile.

• See Profile Manager - Create, remove or switch Firefox profiles
• Or use the Firefox reset. That is simpler, but will remove your Firefox extensions, so you may wish to bookmark extension's homepages before attempting that
  Refresh Firefox - reset add-ons and settings

Hey christ1, I actually read this article before starting this thread : ) I tried everything in that article but none worked...

John99 thank you! : ) Problem fixed. But I'm still wondering why that problem occured. Will try to figure it out. Merci!

Glad it is working again.

We often say Firefox is highly customisable with many addons available.

That has the downside that odd and unexpected effects and interactions can sometimes occur.

Yep I watched a documentary of Mozilla Firefox in which there was an interesting line (not verbatim) "since programmers just do their own modules of Firefox and then they gather and piece the modules together, so when the final thing works everybody cheers but none knows how". Haha, dat's cool : )