Could you possibly submit the gif in a bug to Mozilla? They’d want to fix that…

Just tried, it's still not working well.

edit: Fixed now.

It's still hanging firefox for me. You can install firefox and try it yourself: https://getfirefox.com

No problem here on FF 48.0a2

It's not the gifs it's the scroll event listener causing a redraw every time.

Nope. Site still completely saturates a core, but only during scroll, not during idle.

Looks like something related to repaints caused by a jquery scroll event http://i.imgur.com/mFL9ZYN.jpg

1 CPU still pegged on firefox.

But otherwise, Reason looks very cool. A nice mashup of technologies to create something that certainly looks more useful than the status quo. I hope this takes off, but I think the biggest challenge nowadays, even for good technology, is finding an audience amidst a plethora of choices. Technology, as always, is a popularity contest.

Thanks for the (many) reports! It's been fixed for a while. No excuse for poor performance!