Hi, I upgraded my MBA mid-'11 to ML last week, and generally speaking I love it. I liked lion too, but the improvement in Safari alone is worth the upgrade. One thing that's popped up that is annoying me, though: I've noticed that when I use the File-Open dialog in Safari and scroll down, the screen flashes. It only seems to happen with Safari, and it MAY be due to something I've done. I tried to replicate the behaviour on the guest account and didn't work, mainly because there's obviously nothing in the guest account and thus nothing to scroll! Shall try again, but thought I'd ask here to see if anyone had seen this themselves. I did a search, both here and through Google, but no joy. All the results were about Adobe Flash, which i don't have installed. EDIT: worked it out. It was my Better Touch Tool settings. I tried to delete the thread, but doesn't seem to be a button for it.