TypeError: Cannot read property 'parentNode' of null

Code:

TypeError: Cannot read property 'parentNode' of null

This error appears every now and then. It appears when this function and the red line is called:

Code:

addListItem: function(index, record) {        var me = this,
            dataview = me.dataview,
            data = dataview.prepareData(record.getData(true), dataview.getStore().indexOf(record), record),
            element = me.element,
            childNodes = element.dom.childNodes,
            ln = childNodes.length,
            wrapElement;


        wrapElement = Ext.Element.create(this.getItemElementConfig(index, data));


        if (!ln || index == ln) {
            wrapElement.appendTo(element);
        } else {
            wrapElement.insertBefore(childNodes[index]);
        }
    },

It is from the Sencha-Class: http://ift.tt/1zbuflU

What can I do?

TypeError: Cannot read property 'parentNode' of null