The problem is that the QButtonGroups are never made part of the hierarchy, so they have no effect.
btw: when posting code try to add the neccessary parts to make it runnable:
from PyQt4 import QtGui
import sys
class Test(QtGui.QWidget):
def __init__(self):
super().__init__()
layout = QtGui.QVBoxLayout(self)
gBBackupFromIntExt = QtGui.QGroupBox()
layout.addWidget(gBBackupFromIntExt)
bGBackupFromIntExt = QtGui.QButtonGroup(self)
self.rBBackupFromExt = QtGui.QRadioButton()
bGBackupFromIntExt.addButton(self.rBBackupFromExt)
layout.addWidget(self.rBBackupFromExt)
self.rBBackupFromInt = QtGui.QRadioButton()
bGBackupFromIntExt.addButton(self.rBBackupFromInt)
layout.addWidget(self.rBBackupFromInt)
gBBackupToIntExt = QtGui.QGroupBox()
layout.addWidget(gBBackupToIntExt)
bGBackupToIntExt = QtGui.QButtonGroup(self)
self.rBBackupToExt = QtGui.QRadioButton()
bGBackupToIntExt.addButton (self.rBBackupToExt)
layout.addWidget(self.rBBackupToExt)
self.rBBackupToInt = QtGui.QRadioButton()
bGBackupToIntExt.addButton (self.rBBackupToInt)
layout.addWidget(self.rBBackupToInt)
a = QtGui.QApplication(sys.argv)
t = Test()
t.show()
a.exec()
this should fix the problem.