Click on the Firefox menu icon. (Three lines at top right of screen.)

   Click on Preferences.
   Choose the Privacy.
   In the History section choose Firefox will: 'Use custom settings for history.'
   Uncheck 'Remember search and form history.'
   Click OK.

Enter about:config in the URL bar and set browser.urlbar.autoFill = false.

Thanks: the about:config command to toggle the flag to :false worked!

Viola’! This worked perfectly; Thank You! Your skills are asset to Mozilla....