parent = treectrl2->AppendContainer( wxDataViewItem(0), "Root 1", 0 );
child = treectrl2->AppendItem( parent, "Child 1", 0 );
child = treectrl2->AppendItem( parent, "Child 2", 0 );
parent = treectrl2->AppendContainer( wxDataViewItem(0), "Root 1", 0 );
child = treectrl2->AppendItem( parent, "Child 1", 0 );
child = treectrl2->AppendItem( parent, "Child 2", 0 );