Zoom out problem of FloatCanvas Demo

Hi all,
I have tried the wxPython-demo-4.0.6, the zoom out behavior in FloatCanvas demo does not lock at location I clicked:

  1. Open demo frame, it shows some graph objects around location (0,0)
  2. Trigger zoom out mode from NavCanvas toolbar
  3. Left-click at (0,0)
    And then it does not zoom out at (0,0) but at (232,102), so I cannot see those graph objects in center of canvas.
    What can i do to “zoom out” at some location like “zoom in” does?