What will happen, if there are 3 changes in 2 years?
This solution may turn out to be too casuistig (can we say this in English?) in 5 years.
It is up to you, I would work with a label or a speed button, which you can color blue by code if the user selects one item.
Such a label, panel or speedbutton can even be invisible if the combobox is "off".