GetPosition() bug with position of -1 (or maybe SetPosition() bug)?

[7stud]

Here is a simpler demonstration of the problem:

import wx

app = wx.App(redirect=False)

frame = wx.Frame(None, -1)

frame.SetPosition((22, 32))
print frame.GetPosition()       #(22, 32)

frame.SetPosition((-2, -2))    
print frame.GetPosition()       #(-2, -2)

frame.SetPosition((50, 50))

frame.SetPosition((-1, -1))
print frame.GetPosition()       #(50, 50)

frame.Show()
app.MainLoop()


Is it a bug in SetPosition()?  It appears that that setting the 
coordinates to -1 is ignored.