There are several POS Operations which not visible by default. The form Operations (Retail - POS - Operations) has a default filter, so that only records where "User Operation" is marked are shown.

If you want to see the hidden Operations, move the cursor to User Operation", right click and select "Filter by field", Then enter "No" or "0" click on "OK":

 

Now you see all operations which are hidden by Default and can attach them to Permission IDs.

 

 If you always want to see the operations when openeing the form, you can either mark "User Operation" and update the lines. Alternatively you can comment out the code which filters the operations in the form: