Returns the index of the inputed editor, or -1 if not found.
        
        :param      editor | <QtGui.QWidget>
        
        :return     <int>

def indexOf(self, editor):
        """
        Returns the index of the inputed editor, or -1 if not found.
        
        :param      editor | <QtGui.QWidget>
        
        :return     <int>
        """
        lay = self.layout()
        for i in range(lay.count()):
            if lay.itemAt(i).widget() == editor:
                return i
        return -1