Called when a card is selected by clicking on the
        card or reader tree control or toolbar.

def OnDeselectCard(self, card):
        """Called when a card is selected by clicking on the
        card or reader tree control or toolbar."""
        SimpleSCardAppEventObserver.OnSelectCard(self, card)
        self.feedbacktext.SetLabel('Deselected card: ' + repr(card))
        self.transmitbutton.Disable()