Select a product in a combo box and the remaining products are displayed in red

  In vanilla 8.1.1 product configurator you have a product class relationship and there is a constraint that the quantity on the relationship = 1.  The product configurator User Interface control for the relationship is a vanilla "Combo Box JS" and after you select a product then the remaining products in the combo box are displayed in red. The user is expecting that the other products would be displayed in black as they are valid products and can be selected without an error.

 

If you select no product (blank) in the combo box then all products return to the black color. The problem is that once a product has been selected then the user interface of the configurator thinks that the selection of another product will break the constraint rule where the quantity on the relationship must be 1.