The ExtJS form.removeAll() function seems to not work well: the form items are deleted but the table cell are still there.
I try to do a manual deletion but it leads to a JS error later

var table = this.el.child('div.x-panel-bwrap div.x-panel-body table.x-table-layout tbody').dom;
while (table.firstChild != null)
{
    table.removeChild(table.firstChild);
}