Aeomin

ah I miss read it. I thought it was going to be along the line with listener.

For simple ones, using existing functionality. Some complicated ones I just use hook. The goal for validation is not saving data if it didn't pass. So callback isn't ideal as it is not some kind event chain I can break.

If formPostSave triggers after form is saved. How would custom validation work?

Would it be possible to add pagination for "Manage Your Purchases" page? When as user have many purchases, this became a giant page since it displays everything that the user have purchased.