Yes, the kind of form does matter. The type of formatting you're speaking of can only be done in a Continuous view form using the Conditional Formatting from the menu. The only way to do conditional formatting from code is to use the Form_Current event, and this means that when you move to a record where "Ignore" is the cbo value, all fields for all records will turn gray. When you move to a field with "Just Placed" they'll all turn green and so fourth.
The reason for this is that a form really only has one of any given textbox; each record has a different instance of this same textbox . If you have a textbox named "Customer" for instance, your form only has one textbox of that name, so if you change its color, every instance of that control will change color.
On a Single view form, this doesn't matter, because you only see one record at a time.