.expander {
    position: absolute;
    top: 5px;
    left: 5px;
    width: 16px;
    height: 16px;
    padding: 4px;
    background: white url(https://github.com/openxe/django-ace/diff_blob/1993c731626a44139b97d2d9fca8f4f4023f107a/django_ace/static/django_ace/img/expand.png?raw=true) center center no-repeat;
    z-index: 99999;   
    cursor: pointer;
}