In a project I'm working on, I've enabled categories for attachments using:
In the edit attachment screen in the Media Library you see the normal list of checkboxes, but in the upload modal categories are presented as a comma-separated list of slugs in a textfield, as if they were a non-hierarchical taxonomy. I'm wondering if it's possible to replace this textfield with a list of category chechboxes. I'm trying to do it myself, but there is little documentation about the 3.5 upload modal.
Thanks in advance