Forms :: Using Combobox In Continuous Subform To Update A Record

I have a continuous subform of 'static data' whose record source is a SELECT query across multiple linked tables.

Most of the fields are locked and purely there for information purposes but I need to be able to allow end users to change one particular field in each record if they need to - choosing a value from a predetermined list (i.e. one of the tables)

Usually, when I need to do this, I add a command button to the subform and use that to open a separate pop-up form specific to that record, from which the user can make whatever changes they like and then update the record. So in this scenario, a simple unbound combobox linked to that table, on that separate form, would work quite easily.

But I would prefer if users could make their changes directly from the subform without (yet another) pop-up form required each time, to make managing these records more fluid and less time-consuming.

So my thought was to use a bound textbox in the continuous subform (to take the existing value for each record), hide it and overlap it with a visible unbound combobox whose row source is the table of available options and whose default value is driven by the hidden bound textbox. And then to use the AfterUpdate event of the combobox to run the UPDATE query on the record in question.

However, while the combobox is getting the correct default value and the correct list items, I can't make a selection from it. Now I am aware there are 'issues' with using a combobox in a continuous subform but I was hoping I could circumvent them by not binding it.