UV version: universalviewer@4.0.25

I'm submitting a: bug report => please fork one of these codesandbox examples with a repro of your issue and include a link to it below

Page area

thumbnails

Issue description

Inside the contents sidebar (left), keyboard users cannot activate images from the thumbnails. They can tab through them but it is not possible to then activate the image to make it display in the image viewer (in the same way a mouse-click would).

Steps to reproduce

1. open this manifest
2. Tab to any of the thumbnails in the left-hand sidebar (except the currently active one)
3. Try to activate the image to display in the main image viewer

Expected behaviour

pressing return key will switch the image in the main image viewer to the selected thumbnail's image

WCAG criterion

2.1.1 Keyboard (Level A)

Related code

<div class="thumb oneCol" tabindex="0"><div class="wrap" style="height: 91px;"><img src="https://images.eap.bl.uk/EAP500/EAP500_1_1/2.jp2/full/90,/0/default.jpg" alt="2"></div><div class="info"><span class="label" title="2">2&nbsp;</span></div></div>