ALV Grid Dropdown Click Event

I have created an ALV grid with a dropdown as one of the columns. This all works fine, except that I want to be able to react to a change in the value of each line's dropdown.

Currently I am reacting to the DATA_CHANGED event of the ALV grid, but that is too late. This event is only triggered if you change the value of the dropdown and then hit enter, or click on another cell or row.

I want to be able to react to a change in the value immediately without having to lose focus of the dropdown.

Is this possible?

As an example, I have a table of records with one column as a dropdown called "Reason". A change in "reason" should change which fields in the row are editable. I'm sure I could just make sure to call the check_changed_data method before saving but I am hoping for a more user-friendly approach where as the new value is selected, the columns in the row can change to their required editable status.

Of course points will be awarded.