Tried multiple times to edit a seed/map from creative to survival the game doesn't allow the switch. However, once I try it I can no longer fly in creative. Also you can edit the name of the seed/map and it appears to work however when you go BACK it doesn't save. I realize this is multiple issues but I wasn't sure if they were all tied to a unified problem within the edit mode/screen. So I listed them together. Sorry...
The seed option is only used to show the seed, i don't think you are supposed to be able to edit the seed