Ctrl+Tab

def tab_navigate(self, delta=1):
        """Ctrl+Tab"""
        if delta > 0 and self.currentIndex() == self.count()-1:
            index = delta-1
        elif delta < 0 and self.currentIndex() == 0:
            index = self.count()+delta
        else:
            index = self.currentIndex()+delta
        self.setCurrentIndex(index)