Want to hide 2 workflow values from dropdown for future transactions

I’m trying to hide two specific values from the Workflow attribute on the quote for future transactions and want to retain the history of the past transaction where either of the value is selected. I have changed Constrained Menu Option Behavior = Hide.  Here’s what I’ve tried and what I’m seeing:

 

1.Constraint Rule (Constrained Menu Option Behavior = Hide):

a)Successfully hides the two values.

b)However, the system still requires a selection from the Workflow dropdown, which blocks quote processing if nothing is selected.

2.Access Rule (Hide Attribute):

a)Hides the Workflow attribute entirely on the quote, which isn’t desired—we only want to remove the two values, not the whole field.