There is an issue using the GroupModelArray and the databinding, everything is great when first loading up but when opening and closing groups things really do start to go wrong.

Additionally when you use the model menu and press "Group" there is also an issue. This probably isn't related though as it is already present in the current demo.

I have attached some code, this is taken from the demo and is a maven project so it is easy to setup and run using eclipse! It could be the way I have implemented it, though I have done it the way it states in the Javadoc & docs, if so it may be a docs issue .