See attached!
column `id` has bee a PK and “PK”, “NOT NULL” and “AUTO” have all been checked.
Now I don't want it to be PK any more and try to uncheck all three boxes.
It is not possible to uncheck the “NOT NULL” box 'in the first run'. i have to uncheck “PK” and “AUTO” save changes, then open ALTER TABLE once more. Now I can uncheck “NOT NULL” and save.
Tested with SQLyog 5.0 an 5.01 (non-public) Beta as well