It disables deletion of modeless ShelveDialog, started from console widget.
It doesn't matter for modal dialog, because PyQt treats QDialog.exec_() as a special case:
> int exec() > [...] > // Transfer ownership back to Python (a modal dialog will probably have the > // main window as it's parent). This means the Qt dialog will be deleted when > // the Python wrapper is garbage collected. Although this is a little > // inconsistent, it saves having to code it explicitly to avoid the memory > // leak. > sipTransferBack(sipSelf);