Doesn't Firefox use the default OS scrollbar? I believe Chrome has their own custom scrollbar, and it allows developers to replace it. For instance, in Trello on Firefox, I see my big native (read: usable) scrollbar on the bottom and in card lists, while in Chrome they're just a thin little line.

Agreed. I noticed this too, would be great if the FF devs could implement that very useful feature. It gives an instant overview of the search hit distribution on the page.

For me, highlighting all occurrences and ctrl/cmd+g (next) is enough. Jetbrains idea does the highlight in scrollbar but I don't find it useful.

If a method is used several times at the top of the page, and you want to find out if it's used elsewhere, without the highlights, you don't know that. You have to hit Next until you make sure it's nowhere else. With the highlights, you immediately see that the block you're looking at is it, and you can move on to a different file.

It also doesn't highlight all search results on the page, only the currently selected one. FF on page search is my biggest complaint.

What is the daily use case? Sounds useful, but daily?

Browsing a large code repository. The scrollbar highlights allow me to "eyeball" the page and go to the general locations quickly rather than hitting Next a thousand times (which feels primitive as hell anyway), especially when a block of code has the same keyword used many times and I need to move on to the next block.

I tried Firefox for a while but I rely on that feature around once or twice a day and I preferred using Chrome for those browsing sessions. So I dumped Firefox and switched back.

Ah, I think I just avoid using a browser to browse a code repository. Swiper/helm in emacs are far superior for searching a repository. Unless I am looking at more than what I can checkout locally... which, I typically don't need to do.