The URL bar will do this. This is normal.

See also:

• http://kb.mozillazine.org/keyword.URL
• http://kb.mozillazine.org/Location_Bar_search

Actually showing history *isn't* normal if your settings exclude it.

Please list any extensions you have installed as there might be a feature conflict

• Tools
• Add-ons
• Extensions

Or

create a fresh profile, make the settings changes desired, and compare to your current profile

http://kb.mozillazine.org/Category:Profiles

Assuming you use windows (I don't):

http://kb.mozillazine.org/Creating_a_new_Firefox_profile_on_Windows

There would only be a problem if you see entries without a highlighted star indicating that it aren't bookmarks.

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe mode start window or otherwise make changes.

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

I would like to know if downgrading to an earlier version of Firefox would help? This problem only started when I upgraded my Firefox. (Unfortunately I cannot remember which version I had before.)

It's really hard work following all the instructions in this and the other thread, when you don't know much about computers. I want someone at Firefox to fix this, because they caused it. I didn't do anything else to my computer than updated Firefox.