Keyboard bindings

        def shift_up(event):
            tree = event.widget
            cur_item = tree.focus()
            prev_item = tree.prev(cur_item)
            _parent = super(Treeview, self).parent(cur_item)

            if self.root_selection < cur_item:
                tree.selection_remove(cur_item)

            if prev_item:
                _children = tree.get_children(prev_item)

                if _children and tree.item(prev_item)['open']:
                    self.select_tail(prev_item)
                    prev_item = tree.focus()

                tree.selection_add(prev_item)
                tree.focus(prev_item)
            elif _parent:
                tree.selection_add(_parent)
                tree.focus(_parent)

            return 'break'

        self.bind('<Shift-Up>', lambda e: shift_up(e))

        def shift_down(event):
            tree = event.widget
            cur_item = tree.focus()
            next_item = tree.next(cur_item)
            children = tree.get_children(cur_item)
            _parent = super(Treeview, self).parent(cur_item)

            if self.root_selection > cur_item:
                tree.selection_remove(cur_item)

            if children and tree.item(cur_item)['open']:
                cur_item = children[0]
                tree.selection_add(cur_item)
                tree.focus(cur_item)
            elif next_item:
                tree.selection_add(next_item)
                tree.focus(next_item)
            else:
                while not tree.next(_parent):
                    _parent = super(Treeview, self).parent(_parent)
                    if not _parent:
                        tree.focus(cur_item)
                        return

                cur_item = tree.next(_parent)
                tree.selection_add(cur_item)
                tree.focus(cur_item)

            return 'break'

        self.bind('<Shift-Down>', lambda e: shift_down(e))