Hi there,
I've noticed that it's not possible to edit the type of a field.
E.g. I think it should be possible to change a dropdown (single) to dropdown (multiple), checkbox, radio etc. as the values can be kept, it's just a matter of visualization.
Example: I've manually edited the field in the db table jos_comprofiler_fields and changed the type from "radio" to "select" and it works...
thus said, why not letting the user edit the type of a field?