About two or three weeks ago Adobe updated their Flash player, from that point on flash based stuff in FF has scrolled vertically with a lot of glitches and is a real mess. The recent FF 13.0.1 update seems to have improved things a little but it's still not as it was.

Lots of screen re-draw issues here and feels sluggish.

hello mjg263, firefox 13 introduced smooth scrolling by default - it might not work well on older hardware.

please either try to update your graphics driver or if this does not improve the matter you can disable smooth scrolling in firefox/tools > options > advanced > general.

Hmmm...turning off Smooth scrolling AND use hardware acceleration seems to have solved my problems. My graphics card is a Nvidia GeForce GTS 240 ... not that shabby.

Thanks very much, madperson. Now I'm not a mad person anymore! The smooth scroll switch got turned on with the last update, and turning it off solved my problem. Why would they change my personal preference settings like that? Caused hours of grief and frustration trying to get back to the way it was. Only bad experience I've EVER had with FF!

Any idea when FF is going to fix this? It works fine with IE, so it seems like a FF problem! I updated my video driver, turned off smooth scrolling, and nothing helped.

Switching off the smooth scrolling fixed it for me, but I know there are other people who have had deeper issues. Someone mentioned something about using the old version of FF to fix it?

Firefox sometimes was very very slow and the web pages took ages to download, I sometimes even can't download it and have to restart my computer again. I really hate it since when I restart my computer again, all the things and websites I'm using and working have to restart again. I really hate this! But it never happens in google Chrome which is more stable. The only reason I use Firefox is that it has the toolbar like the old IE and I can't transfer the data from IE to Chrome. But I really hate the bug that Firefox has and I wondering why they don't fix it!