I have searched for some kind of solution to this, and I'm not sure exactly where to try and post. Here goes, I hope someone out there may have an idea to fix this.
I have a content type with an audio field set up using the media file selector.
It will allow the creation of the content properly.
If you need to go in and edit though, the preview icon is rendered differently as it does not allow to select, edit or remove. The buttons are there but do nothing.
I created another content type and referenced the same files, and the select, edit and remove work.
My current content type has over 1000 already created so I don't want to have to recreate the content type to fix it.
Someone online said that my content type may be corrupted in the DB, but I'm not sure.
I used firebug and noticed that the broken one does not show the .media-widget .preview css like the correct one does. I have no idea why.
I've taken a couple of screenshots. One with the correct preview icon, and one with the broken.