Yesterday I have tried some things. One of the problems was the switch that I set on every page. I have used a wrong custom field id and rename them. After that I have to save each page manually to get it back to work. In the code I couldn't receive the new id (group field) and switched back to the old one.
Please can you give me a link or information about:
How can I correct rename an field ID?
How can I correct remlove a field? What about the information that is stored?