You can’t really extend the maxlength from what is recorded in the database field for it.

Alt Handing Unit Label is recorded in the DB as a varchar2(25) type of field, means 25 max length.

Updating the Page Designer will let your client (e.g. Browser) put in more data in the field, but as soon as you save, the maxlength property of the field (25) will kick in and error out.

In short, the maxlength on page designer can only help you if you want to force the length to be LESS than the max set database length, if you wanted your users for instance to never use more than 10 characters, that would work, but you can’t go ABOVE the max length at database level :)