Override Qt method.

        Returns the widget size hint (based on the editor font size).

def sizeHint(self):
        """Override Qt method.

        Returns the widget size hint (based on the editor font size).
        """
        fm = QFontMetrics(self.editor.font())
        size_hint = QSize(fm.height(), fm.height())
        if size_hint.width() > 16:
            size_hint.setWidth(16)
        return size_hint