Great enthusiasm, kudos. However, a couple of futures are lacking in all similar FF addons:
1. It would be great if you could implement virtual scrollbar with indication where matches occurred within a page. Something like developer of the "HightlightAll" addon achieved. I know this is hard to implement since I'm using FF on Kubuntu, but it is a game changing feature.
2. Another one (if even possible), would be nice if there is an option for search window to stay open when we change tab.
Nevertheless, great addon. Keep up...