Flipview weirdness - crazy DIV tag

Question

I have a flipview but having some weirdness with inline CSS that's messing up.

In DOM Explorer I see this 

div style="left: 685500px; width: 1371px; height: 400px; overflow: hidden; ;">

just above my win-item class.  What is that?  No idea what it means but 400px height is killing me!

My html.

    <div class="itemtemplate" data-win-control="WinJS.Binding.Template">
        <img class="item-image" src="#" data-win-bind="src: backgroundImage; alt: title" />
        <div class="item-info">
            <h4 class="item-title" data-win-bind="textContent: title"> </h4>
        </div>
    </div>

    <!-- The content that will be loaded and displayed. -->
    <div class="flipViewPage fragment">
        <header aria-label="Header content" role="banner">
            <button class="win-backbutton" aria-label="Back" disabled></button>
            <h1 class="titlearea win-type-ellipsis">
                <span class="pagetitle"></span>
            </h1>
        </header>
        <section aria-label="Main content" role="main">
            <div id="reviewFilpView" class="itemslist" aria-label="List of this group's items" data-win-control="WinJS.UI.FlipView" data-win-options="{ selectionMode: 'none' }"></div>
        </section>
    </div>

Thanks

Paul