While building the most recent ND.edu, I ran into a little iOS 5.1 bug (at least I think it’s a bug). One of the features of the site is a menu with “position:fixed”. Another feature is we load a number of top-level pages on to the homepage for larger screens. So the functionality is such that, if someone is on the homepage, and they click one of the main navigation items, we scroll them to that section rather than loading that page. But we quickly ran into an issue on iOS devices.
When jQuery is used to scroll the content to a specific spot, an element with a fixed position visually appears where it should, but cannot be clicked/touched immediately after the scroll. After some tinkering, I discovered that even though the navigation stayed in place as it should, it was technically still in its previous location in the viewport. So for instance, if you click on one of the nav items while at the top of the screen, the viewport will scroll down the page. But if you inspect the “top” of the navigation, it reports that it is still in its original position. However, as soon as you manually scroll the page, its position is updated and can once again be interacted with.