I am uncertain if the enum mechanism is the correct or even the only option here. I was merely following the EzBug example.
Here is my scenario - with reference to a conventional combo box. Let say I have the combo that holds the title of a person as part of the person's full name. The combo is programmatically populated with the following items - Dr, Mr, Mrs. With the enum mechanism, there is no option to add another title such as "Professor", when registering a new person. How do I get around this for combo, and maybe on a broader level as it include Sapphire.
The scenario you have described would be better served by a plain string property with @PossibleValues or a custom PossibleValuesService. See @PossibleValues.invalidValueSeverity and PossibleValuesService.getInvalidValueSeverity() if you wish to specify that values outside of the provided possible values are ok.
The presentation used will be a text box with content assist and a browse button. There is also an enhancement request to provide a secondary presentation of an editable combo box.