A drop-down list has a selection field with one choice displayed as the default value, and a hidden list box. When the user selects the down arrow displayed to the right of the field, the list box appears. The user can then select a line from the list box to change the choice displayed. In ESL for Windows, the initial value of the selection field must exactly match one of the entries in the list box, or else the selection field is empty.

Drop-down list boxes are useful for providing single-selection list- box functionality, while maximizing the use of screen real estate.