How to implement this UI
<p>Just curious if the tab bar UI element in screenshots is some built in class or customized.
If it is customized, then please give me a hint on what classes I might check to have something like that.</p>

<p>The first screenshot is initial tab bar. When I tap on the last icon the tab bar smoothly(animated) resize itself as on second screenshot. If I press the edit button the icons are shaking(as on iPhone home) and I'm able to arrange them.</p>

<p>first</p>

<p><img src="http://img686.imageshack.us/img686/3899/photo2aw.jpg" alt="tab bar"></p>

<p>second</p>

<p><img src="http://img38.imageshack.us/img38/5673/photo3kq.jpg" alt="more buttons"></p>
