I just installed Firefox 1.5 on Vista RC1 and a funny thing happened... most websites I visit are bouncing up and down. Well, actually, this didn't start until I changed the display a tiny bit. By default, Firefox comes with 3 toolbars -- the menu, navigation/address/search, and bookmarks. Since I'm all about minimizing space, I move the Bookmarks Toolbar Items to the right of the menu so its flush against the Activity Indicator. The second I moved this, the "Thanks for installing Firefox" page started bouncing up and down. The main window stays still, but the page contents, scrollbars, and page icon in the address bar all bounce about 3 pixels. It's kind of funny, until it gets annoying... which is fairly quickly. Try it out for yourself.