code: def create_widget(self):
          
          d = self.declaration
          style = d.style or '@style/Widget.DeviceDefault.PopupMenu'
          self.window = PopupWindow(self.get_context(), None, 0, style)
          self.showing = False
docs: Create the underlying widget.
  
          A dialog is not a subclass of view, hence we don't set name as widget
          or children will try to use it as their parent.