If you have been using Firefox for a while then you might encounter this frequently asked problem.Turn off the address bar drop-down list in Firefox to prevent your browsing history being known by others.Here is an easy way that just set the number of the addresses in drop-down list to 0 and it won’t show browsing history anymore.
Type this in the location bar and click “I’ll be careful,I promise!” in next screen:
Input following text in Filter area and hit enter:
Right-click on this line,choose “Modify” and set its value to 0
BTW:Navigate to Tools->Options(or Edit->Preferences for Firefox in Ubuntu) and in Privacy tab you can do more settings for browsing history.