jointjs Reset one cell on mouse down
<p>I am trying to reset a cell on mouse down event. E.g if a user clicks on rectangle I would like to set its <code>stroke-width</code> to <code>1</code></p>

<pre><code> paper.on('cell:pointerdown', function (cellView, evt, x, y) {
        cellView.model.attr('rect/stroke-width', 1);
        graph.resetCells(cellView);
    });
</code></pre>

<p><strong>But I get the error:</strong> <code>TypeError: dia.Graph: cell type must be a string.</code></p>