Build Identifgier http://hg.mozilla.org/mozilla-central/rev/5835bc763be7 Mozilla/5.0 (Windows NT 6.1; WOW64; rv:21.0) Gecko/20130211 Firefox/21.0 ID:20130211031055 This is spun off from Bug 800198 STR: 1) Open this SVG demo: http://www.jasondavies.com/factorisation-diagrams/ 2) Scroll the page with the vertical scrollbar or the middle button Result: Scrolling is slowed down and isn't as smooth as in FF16. After scrolling the page during a while, f you switch to another tab then you come back, there is a slight hang to display the tab with the SVG demo. Regression window(cached m-i) Good: http://hg.mozilla.org/integration/mozilla-inbound/rev/a799b5bff84c Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/17.0 Firefox/17.0 ID:20120801155239 Bad: http://hg.mozilla.org/integration/mozilla-inbound/rev/b077c43a4306 Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/17.0 Firefox/17.0 ID:20120801163038 Pushlog: http://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=a799b5bff84c&tochange=b077c43a4306 And svg.display-lists.painting.enabled = false helps