A race condition can result in the error: 'NoneType' object has no attribute 'geometry'

[f34rdotcom]

• Line
  

  ttkwidgets/ttkwidgets/frames/tooltip.py

  Line 123 in ebaa7d4

  self._canvas.update()

• Version
  ttkwidgets Version: 0.13.0
• Issue
  self._canvas.update() can cause any pending events to be called including _on_leave() event. This will result in self._top_level being reset to None and then the .geometry) call to fail
• partial call stack

  File "ttkwidgets/frames/tooltip.py", line 177, in config
  File "ttkwidgets/frames/tooltip.py", line 125, in show
AttributeError: 'NoneType' object has no attribute 'geometry'

• proposed fix

            x, y = self.master.winfo_pointerxy()
        self._canvas.update()
        # .update() allows background tasks to run could cause on_leave to reset _toplevel to None
        if self._toplevel:
            # Update the Geometry of the Toplevel to update its position and size
            self._toplevel.geometry("{0}x{1}+{2}+{3}".format(
                self._canvas.winfo_width(), self._canvas.winfo_height(),
                x + self.__offset[0], y + self.__offset[1]))