This small example change the Tiny Menu icon of Firefox extension called "Hide Caption" ( ). The default icon is black, I changed to white to combine with dark background themes like my actual Persona ( http://www.getpersonas.com/en-US/persona/2050 ).

Installed addons featured on screenshots:

1) Flagfox (small country flag of website server ip on urlbar) -
2) Tab Mix Plus (reload every menu combined with reload button) -
3) FabTabs (colored tab effect) -
4) Searchbar Autosizer (self-explanatory) -
5) Persona "Gray and Black" - http://www.getpersonas.com/en-US/persona/2050
6) Google Bookmarks Button Reloaded - http://sites.google.com/site/chiu0602/gbbr
7) Smart Stop/Reload (combined stop/reload button) - https://addons