[PyQt] QWidget not deleted with its parent window

Tavian Barnes tavianator at tavianator.com
Thu Nov 3 23:49:03 GMT 2011

I originally posted this on stackoverflow[1], where I learned that
this seems to be a bug in PyQt 4.8.6.  (I'm using Qt 4.7.4 if that's

Basically, the __del__ method of the central widget of a window is
never called.  Example:

#!/usr/bin/env python

from PyQt4 import QtGui

class Preview(QtGui.QWidget):
  def __init__(self, parent):
    QtGui.QWidget.__init__(self, parent)

  def __del__(self):
    print("Deleting Preview")

class PreviewWindow(QtGui.QMainWindow):
  def __init__(self):

    self.widget = Preview(self)

  def __del__(self):
    print("Deleting PreviewWindow")

if __name__ == "__main__":
  app = QtGui.QApplication(["Dimension Preview"])
  window = PreviewWindow()
  # del window

If I uncomment the "del window" line, "Deleting Preview" prints as
expected.  Otherwise, I just see "Deleting PreviewWindow".  Apparently
pyqt 4.8.5 works correctly.

[1] http://stackoverflow.com/questions/7988578/qwidget-not-deleted-with-parent-window

Tavian Barnes

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