Notable cases of excessive reflows:
Hovering over the sidebar links in gmail (updates almost the entire page on each hover)
Hovering over "related videos" links on youtube (updates all of the related videos area, area around the video, video description, and comment area)
A lot of the javascript powered animations/slideshows you see on web pages. (Again, its not uncommon to see almost the entire page being updated here)
A few IE test drive tests like BetaFishIE, Santa's workshop, and the CSS maze solver.
When the above bug is fixed, Gecko should be much better in all of these cases.
That bug is getting close to being done. It fixes a lot of crappyness with excessive layout reflows and painting.
You can see how sometimes Gecko will reflow a much larger area than needed by setting nglayout.debug.paint_flashing to true or installing the following addon: https://addons.mozilla.org/en-US/firefox/addon/toggle-paint-...
Notable cases of excessive reflows: Hovering over the sidebar links in gmail (updates almost the entire page on each hover) Hovering over "related videos" links on youtube (updates all of the related videos area, area around the video, video description, and comment area) A lot of the javascript powered animations/slideshows you see on web pages. (Again, its not uncommon to see almost the entire page being updated here) A few IE test drive tests like BetaFishIE, Santa's workshop, and the CSS maze solver.
When the above bug is fixed, Gecko should be much better in all of these cases.