Android 2.1 address bar causes change in viewport dimensions

I have a page that has a 100% width and height div in it (all surrounding elements are sized accordingly so that it does actually achieve 100% width and height). Below that div I have a second div with a fixed height.

In mobile safari and blackberry everything is fine, when the page loads the dimensions are applied correctly (the top div filling the viewport) and the user can scroll down to reveal the second div. Android 2.1 also applies the dimen开发者_运维知识库sions correctly, but with an added quirk; when the user scrolls down and removes the address bar from the page, the dimensions of the div are recalculated to fill the viewport, causing the content to jump. Ideally I would like the dimensions of the div to remain static when the page is scrolled, but remain 100% so that it will fill the viewport regardless of device size or orientation.

Does anyone know of any way to disable this recalculation?

Thanks for any help you can provide.

The only thing I can think of is to have a Android 2.1 specific negative margin the counters the address bar. Target it by user agent.