尝试通过CollectionViewSource和Converter对HierachicalDataTemplate进行排序时，从不调用Converter

I try to sort a HierachicalDataTemplate via CollectionViewSource and a Converter Class (CollectionViewFactoryConverter), which should be the perfect solution to be able to sort all levels of the treeview. I use a DXTreelist from DevExpress, but I assume this isn not the source of my problem.I try to sort a HierachicalDataTemplate via Col