def SetFocus(self, **kwargs):
        """
        Over-rides normal behaviour of shifting focus to any child.  Prefers
        the one set explicityly by use_as_focus.
        :param **kwargs:
        """
        if self._focus is not None:
            self._focus.SetFocus()
        else:
            # fall back on the default behaviour
            super(_FocusablePanel, self).SetFocus()