'Use the attributes from the input signal if the signal is present
and at least two attributes appear in the domain. If there are
multiple, use the first two. Combos are disabled if inputs are used.'

def resolve_shown_attributes(self):

    self.warning()
    self.attr_box.setEnabled(True)
    if (not self.input_features):
        return
    features = [f for f in self.input_features if (f in self.domain_model)]
    if (not features):
        self.warning('Features    from    the    input    signal    are    not    present    in    the    data')
        return
    old_attrs = (self.attr_x, self.attr_y)
    (self.attr_x, self.attr_y) = [f for f in (features * 2)[:2]]
    self.attr_box.setEnabled(False)
    if ((self.attr_x, self.attr_y) != old_attrs):
        self.selection = set()
        self.update_graph()
