The following code places a button in a window, and then removes the button and
attempts to destroy it. I would expect the button to be deleted, but instead it
remains alive, apparently with no owner on the Python side and no owner on the
C++ side. Therefore rather than producing an empty window on screen, this
produces an empty window with an additional window containing the button (as
the orphaned window becomes a toplevel window). This code works as expected
with PyQt4, so I believe it may be a bug in PySide.

import sys
from PySide import QtGui
#from PyQt4 import QtGui

app = QtGui.QApplication( sys.argv )

# place a button in a window
w = QtGui.QWidget()
b = QtGui.QPushButton( "test" )
b.setParent( w )
w.show()

# query the button's parent - removing this call yields the expected behaviour.
b.parent()

# remove the button and attempt to destroy it
b.setParent( None )
b.show() # so we can see the button if destruction doesn't occur
del b

sys.exit( app.exec_() )