"Add a category" box should minimize when you click on the "Add a category link"

Steps to follow to reproduce:

• in main click "Create a new space" -> box expands
• click again "Create a new space" -> box disappears
• go to a blog post
• click "Add a category" -> box expands
• click "Add a category" again -> nothing happens

Result: It would be nice if the "Add a category" box minimized when you clicked on the "Add a category link".