The "center" column generated by the Draw Tool cannot be edited from the attribute table editor.
This is due to the format of the column in the database which is an array of float8.
Array type is not supported in the editor and should be implemented.

To reproduce, you must:

1. create a new polygon layer with the Draw Tool
2. add a new circle
3. import this new layer into the MapX database
4. open the attribute table editor
5. try to change the value of the "center" column