When link is given to image or text, Unlink command should get enabled. But it gets enabled for text only while remains disabled for images.
To get a better understanding, please refer to the following video:
Posted on:07 Jun 2016 07:38
Not reproducible in latest Edge, Chrome and Firefox with the R2 2016 release of UI for ASP.NET AJAX: http://screencast.com/t/onX2rRUpfKaI