iiif icon not dragging in safari (ok in FF or chrome)

[yulgit1]

https://collections-test.britishart.yale.edu/catalog/tms:10034

In link above, the IIIF icon does not drag in safari (FF, chrome work OK)

<div id="ycba-thumbnail-controls" class="col-xs-2" align="center">
<a target="_blank" href="https://view.collections.yale.edu/m3/?manifest=https://manifests.collections.yale.edu/ycba/obj/<%= @document['id'].split(":")[1] %>">
<img src='https://manifests.britishart.yale.edu/logo-iiif.png' class='img-responsive' alt='IIIF Manifest' title='View Image in full IIIF viewer' draggable>
</a>
</div>