Option to add caption with solid border in 5.1.4 has vanished

I have a blog post with a list of Fellows for a leadership programme that was created a few weeks ago in a previous version. All have an image and a blurb about each candidate. I had to update the post as one of the candidates fell out. I've added in the replacement candidate, but the ability to create a line around the image and caption has disappeared in version 5.1.4. Previously it was "caption solid border".

See Kayode Ogunro on the link below.