Strange behaviour on 'expandingdelegates' example

f I open the expandingdelegates example found in the SDK 1.1 beta and change line 66 in 'expandingdelegates.qml' from:

height: 70

to:

height: listView.height/listView.count

I experience strange visual behaviour. Best described as: "When closing the expanded delegate it jumps back to its original position and is not animated smoothly".

Can this be a bug or am I missing something?