"TreeView" widget issue

remove_node_issue.py

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.gridlayout import GridLayout
from kivy.uix.treeview import TreeView, TreeViewLabel


Builder.load_string('''

<Test>:
    rows: 2

    Tree:
        id: tree

    Label:
        id: label
        text: 'selected node:\\n{!s}'.format(tree.selected_node)

    Button:
        size_hint_y: None
        height: 40
        text: 'Remove selected node'
        on_press: if tree.selected_node: tree.remove_node(tree.selected_node)

    Button:
        size_hint_y: None
        height: 40
        text: 'Update label'
        on_press: label.text = 'update:\\n{!s}'.format(tree.selected_node)

''')


class Test(GridLayout):
    pass


class Tree(TreeView):

    def __init__(self, **kwargs):
        super(Tree, self).__init__(**kwargs)
        self.add_node(TreeViewLabel(text='Item 1'))
        node = TreeViewLabel(text='Item 2')
        self.add_node(node)
        self.add_node(TreeViewLabel(text='Child'), node)


app = App()
app.title = 'test'
app.root = Test()
app.run()