All of the fields must be filled.
You cannot swap a section with a page.
You must first select a group before adding a user to it.

There is a common problem in XSLT where you have two XML of the same xPath (whether it be absolute or relative) that end up taking the same template. In many scenarios you do not have the ability to modify the XML so that it suits your XSLT and you must therefore turn to the mode trick to create seperate templates.