The `event` attribute makes the selected node and its descendants trigger an arbitrary event when clicked (mousedown/touchstart). This event is triggered on the view itself and the paper. The paper handler is called with the signature `cellView`, `evt`, `x`, `y`, while the cell view handler is called only with `evt`, `x`, `y`.

    element.attr({
      image: {
        // pointerdown on the image SVG node will trigger the `element:delete` event
        event: 'element:delete',
        xlinkHref: 'trash.png'
        width: 20,
        height: 20
      }
    });
    // Binding handler to the event
    paper.on('element:delete', function(elementView, evt) {
      // Stop any further actions with the element view e.g. dragging
      evt.stopPropagation();
      if (confirm('Are you sure you want to delete this element?')) {
          elementView.model.remove();
      }
    });