iPhone UINavigationBar: Why does it resize in landscape orientation?

Question

Hi,

I searched all the web but did not find a clue:

I've got a UIView in a UINavigationController in a UITabBarController—not that unusual, I guess.

First of all an image: http://img824.imageshack.us/img824/426/navbari.png

The app starts in portrait mode (1)

When I now rotate the device to landscape mode the app looks like in (2)

After tapping on tab "B" and then going back to "A" the UINavigationBar shrinks in height and everything fits (3)

Rotating the device back to portrait gives me the layout in (3)

Tapping "B" and "A" again results in the first picture (1)

So, what the f*** is happening here? Why is the UINavigationBar resizing? Can I suppress this? Will this resolve the clutter in image #2?

:/

Thanks for your help :)