On iOS 15 scrolling within an element causes the window to resize / toolbar to disappear, regardless of if you have the top or bottom toolbar. On iOS 14 this would only happen when the body scrolled. See gifs below, note - the yellow area is a div with overflow scroll and the body is not scrolling.
iOS 15
iOS 14
Code example here: https://codesandbox.io/s/ios15-scroll-example-u7toi
Is this new behaviour intended or a bug? Is there any way to disable it as it makes quite a few websites look a little strange now!

