Rated 4 out of 5 stars
It is a cause of disability such extensions like Search Scrub https://addons.mozilla.org/en-us/firefox/addon/search-scrub/ and SearchLoad Options https://addons.mozilla.org/en-us/firefox/addon/searchload-options/
Rated 5 out of 5 stars
Useful addon but can become more convenient. It is necessary only increase the maximum number of search shortcuts from 6 to at least 10 and number of history and bookmarks from 10 to at least 20 in preference.