    HighlighterView.prototype.MOUNTABLE

If the property is true, the highlighter view is attached to the DOM.

If the property is false, it is not attached upon highlight.

The default is true.

    const ChildView = joint.dia.HighlighterView.extend({

        // HighlighterView `el` is not meant to be appended
        MOUNTABLE: false,

        highlight(cellView, node) {
            node.setAttribute('my-attribute', String(cellView.model.get('highlightAttribute')));
        },

        unhighlight(cellView, node) {
            node.removeAttribute('my-attribute');
        }

    });