<template name="imageViewerViewport">
    <div class='imageViewerViewport'
        oncontextmenu='return false;'
        unselectable='on'
        onselectstart='return false;'
        tabindex='0'>
    </div>
    <div class='viewportInstructions'>
        Please drag a stack here to view images.
    </div>
    {{>viewportOverlay}}
    {{>loadingIndicator}}
    {{>viewportOrientationMarkers}}
</template>
