Sales/Purchases: Change Enter Sales/Purchase window listed options (bottom of window)

I'd like to suggest that this area is changable with secruity features ticked. It doesnt affect the figures so i cant see why it cant be.  Eg; Salesperson, Comment, Ship, Promised Date, Referral Source etc.  If there is a reason this is locked could this please be explained?  I know i can if i change security settings then change them back, but it would be far simplier to be able to make the changes with out having to do this. 

Look forward to being able to make changes in this area. 

"Being able to change the bottom section of Sales/Purchases"