By default all FORMS ($optiontype F) or manual Forms ($optiontype m) are automatically protected, unless the Form contains a Table / View ($optiontype V)
In such case, if you have a form with a table inside you need to add the $optiontype p (lower case) for protected.
This is very common on edit pages that contain a table at the bottom, like EDIT CLIENT and it has after the edit form a list of Invoices in a table. Or when there is a for, at the top of a table that is used to generate filters or searches for the table below.
The following example is the Edit Invoice from Billing, it has a Form "F", a View "V", and we want to protect it so we add protection at the end "p".
$editoptiontype = "FVUQWCDEPp";
if it was from the _SECTIONS.php setup we add "p" asd well to the option types, for example here we have a page with View, Form, Live, Delete, Edit, Position and protected.
$SECTION->setOption("VIEW PAGE,VER PAGINA,VOIR PAGE","document",'4',"VFLDEPp",true);