Suggestions in a login drop-down menu that have a key icon in front are login suggestions that you need to remove in the Password Manager.

• https://support.mozilla.org/en-US/kb/password-manager-remember-delete-edit-logins

Suggestions in a drop-down menu without a key symbol are autocomplete saved form data. Suggestions without a key icon are part of autocomplete saved form data that you should be able to remove by selecting this item with the cursor Down key and pressing Delete (Mac: Shift+Delete).

• https://support.mozilla.org/en-US/kb/control-whether-firefox-automatically-fills-forms

Suggestions in a drop-down menu without a key symbol are autocomplete saved form data. Suggestions without a key icon are part of autocomplete saved form data that you should be able to remove by selecting this item with the cursor Down key and pressing Delete (Mac: Shift+Delete).

• https://support.mozilla.org/en-US/kb/control-whether-firefox-automatically-fills-forms

it is the problem, the selecting+DEL doesn't delete the selected item permanently, it is only removed during the action, but when i return to the bar and press the down arrow key, the unwanted item reappear again, whatever it is the search engine bar or any website drop down menu with autofill history, impossible to really delete suggestions, they reappear in the second, like if firefox refused to update the autocomplete history form file with the removed data. i never had this problem until firefox 127.