Detect modifier keypress
modifiers = QtGui.QApplication.keyboardModifiers()
if modifiers == QtCore.Qt.ShiftModifier:
print('Shift+Click')
elif modifiers == QtCore.Qt.ControlModifier:
print('Control+Click')
elif modifiers == (QtCore.Qt.ControlModifier | QtCore.Qt.ShiftModifier):
print('Control+Shift+Click')
else:
print('Click')