I'm opening a ticket to fully explain my issue using the new bar hiding feature on iOS. I want to create a UI which look like a classic iOS/Android app : a fixed navigation bar on the top, the scrollable content at the center, and a fixed tabbar at the bottom.

I use a fixed header and footer with data-position="fixed", and my central content is in a div with a fixed height and an overflow:scroll css property. The issue is the following :

At the beginning the app look like this on Safari (iOS 5 beta 1 / iOS 4.3.3) :
http://dl.dropbox.com/u/14316834/jquery/1.PNG

So the UI look great and the app look exactly the way she should, but if I scroll down by touching the header or footer or when the central content is at the bottom, this is what append :
http://dl.dropbox.com/u/14316834/jquery/2.PNG

Immediatly after that the footer come back to the bottom but my central content doesn't ajust his own height so there is a blank between the footer and the content.

The same problem but inverted come when i scroll the app to the top to show the adress bar, the footer replace itself at the bottom but hide the bottom of the central content.

My proposition is the following : Make the new bar adress hiding feature an option that can be disabled.