Buttons can't launch inline content in prettyphoto on 2.8.1

Hi,
I updated from 2.6.2 to 2.8.1 and discovered that buttons can’t launch inline content in prettyphoto lightboxes anymore.
The example provided by Dude works with the text: https://kriesi.at/support/topic/is-there-a-lightbox-feature-built-in/
… but not with a button:

<a href="#inline-1" class="button" rel="prettyphoto">Open in lightbox</a>
<div id="inline-1" class="aviahide">
<p>This is inline content opened in prettyPhoto.</p>
</div>

I rely a lot on those butons launching prettyphoto lightboxes, is there a workaround to this?

Thanks for your support!