User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b8pre) Gecko/20101124 Firefox/4.0b8pre Build Identifier: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b8pre) Gecko/20101124 Firefox/4.0b8pre I tried to find a suitable existing bug but all were somewhat too much specific or so and therefore I’m filing new one. On the URL given the position:fixed element on the right is bouncing and even getting out of the view when scrolling. I think that there’s been done a lot about those position:fixed elements and before this behaviour was present on many more sites. I thought it is actually fixed but now I see it on this site. Reproducible: Always Steps to Reproduce: 1. Go to www.slevin.cz. 2. Scroll down and up. Actual Results: The position:fixed element on the right is flickering and bouncing. Expected Results: It should stay on its place and should not move.

Sorry, I’ve found out that this is not position:fixed element but that there’s some javascript scrolling function which keep it fixed. So I don’t know how to name this bug but I think it’s still a bug. Only in Chrome and Safari everything is OK and the element stays in its place all the time. In IE, Firefox and Opera I see the problem described.

This seems to be the Code making the DIV "fixed" when scrolling: $(window).scroll(function() { $('#fb_share').css({ 'top':$(window).scrollTop()+75 }); $d = ($(window).scrollTop() > 600)?'block':'none'; $('#top_scroll').css({'display':$d}); if($(window).scrollTop()==0){$('#fb_share').css({ 'top':185 }); } }); No Idea if this good Code or not or if Chrome/Safari is right or not ;)

For that code to not cause the observed problem, the scroll event would need to fire before the scroll is painted. roc, do we do that?

We don't. Let's fix this post-FF4. When all painting goes through the refresh driver, we can have it flush all pending onscroll events before painting.

This is still broken in Firefox 9 but appears to be fixed in Firefox 10 on the beta channel.