GtkTipsQuery::set_labels
void set_labels(string label_inactive, string label_no_tip); 
    
     The label_inactive is shown when the
     tip query widget is not in use, means not activated.
     It is shown the first time when the query has been used
     once. 
    
    
     The label_no_tip is shown when
     the tip query is active, but the widget beneath the pointer
     has no tooltip.