That is the location bar, where you type the address of web pages to go to. You can highlight the entry that you want to remove and press the Delete key to remove it. The location bar has a learning ability that works via bonus points (*) to make entries appear higher in the list, so you need to visit a website more often if you want to see it in that drop down list.

See:

• Remove websites from the address bar suggestions
• Address bar autocomplete suggestions in Firefox

Thanks for your response, Cor-el.

You confirmed I was on the right track, but out of options. On the location bar drop-down list, I already have discovered I can remove junk with the delete key, but am unable with any key to introduce new URLs-- not by even dragging the URL icon to the "star" in the far right of the input box, and simply dropping it (although the screen seemed to indicate the star "swallowed" my donation).

So, you have confirmed this will be somewhat more difficult-- or as you have said, a "learning" situation with FF. Do you happen to know how many times I must search Google before FF gets the idea? Is there a number in the Windows registry or under application data that can be tweaked?

Suggestion for FF feature, and to spare you further user questions of this nature-- the ability to drag URL icons to the star to add items, and the ability to drag icons away from the drop down list. And maybe the option to drag items in the drop-down list to a different order position in the list.

A mini editor might work just as well to manage both list contents and list order.