jQueryUI Sortable Item Incorrect Position While Dragging

Question

I have a jQueryUI sortable list which contains three bootstrap panels, panels 1 and 2 start dragging with the correct initial positions, however whenever you try to drag panel 3 it drops under panel 1 offset from the cursor. Live demo

HTML

<ul id="sortable">
    <li class="col-xs-4">
        <div class="panel panel-default">
            <div class="panel-heading ui-sortable-handle">1</div>
            <div class="panel-body"></div>
        </div>
    </li>
    <li class="col-xs-4">
        <div class="panel panel-default">
            <div class="panel-heading ui-sortable-handle">2</div>
            <div class="panel-body"></div>
        </div>
    </li>
    <li class="col-xs-4">
        <div class="panel panel-default">
            <div class="panel-heading ui-sortable-handle">3</div>
            <div class="panel-body"></div>
        </div>
    </li>
</ul>

JavaScript

$('#sortable').sortable({
    tolerance: 'pointer',
    handle: '.panel-heading',
    placeholder: 'col-xs-4 panel-al-placeholder',
    start: function (e, ui) {
        ui.placeholder.height(ui.item.children().height());
    }
});

CSS

ul {
    width: 650px;
    list-style: none;
    padding: 0;
    margin: 0;
}
.panel-al-placeholder {
    margin-bottom: 18px;
    border:2px solid #f8e287;
    background:#fef9e7
}

Answer 1

I had a similar problem, setting the helper to clone mode worked for me:

$('#sortable').sortable({
    helper: 'clone'
});