fast user switching

I have the same issue in Lion, running 10.7.2 on my MacBook Air.

When switching between users, again both admins, using gestures to scroll up and down does not update, though it is actually scrolling—you just can't see it. Clicking outside of Safari (bringing the Finder to the forefront) permits the window to show you where you've scrolled to, however it is not possible to scroll when bringing the Safari window back into focus. When I do scroll in Safari (again, I can't see it actually scrolling but I know it's happening), the processes for Safari Web Content spike to roughly 50% of the CPU, Safari lingers at about 8%, and Flash is around 4%. I've noticed this issue more often when using Flash, and I've updated to the latest release, but haven't tried removing it to see if that's part of the problem. I haven't used iPhoto but I'll try that and see if I get the same behavior. Quitting Safari will resolve temporarily, but any time I switch between users and try using Safari for less than a couple minutes, I run into this as well.

Just adding my 2c. Having the same problem with Lion's Fast User Switching. The scrolling problem is occurring in Safari and the official Twitter app.

Same problem here. I see it in different apps, but most of the time in Safari (probably because both users use it the most).

I think it happens only when the same app is opened in the other users account.

I can actually debunk that one 🙂 My 2nd account was only created a few days ago to run some email IMAP tests, so I have never launched any app in there apart from Mail and Safari. Twitter definitely wasn't open in the 2nd account.

The bug occurs only sometimes with Safari, but with the official Twitter app it has (so far) happened every single time. At least a dozen times at last count.

I just updated to Mountain Lion and still have this problem (not in Safari but in the Twitter app). Maybe Apple was able to fix Safari but Twitter wasn't able to fix the twitter app. Hope this can be resolved soon.