QML State 'extend' property could use an example (that already exists)

The description of the 'extend' property in QML State Element is rather short and cryptic. Why is this useful to me? How should I do it?

http://doc.qt.nokia.com/4.7-snapshot/qml-state.html#extend-prop

However, looking at an example everything becomes evident:

http://jingfenghanmax.blogspot.com/2010/08/extend-property-of-qml-state.html

So why not integrating that example (or coming up with one of your own) to help developers defining better states? Thank you.