The Pull-Down List

Pull-down lists are similar to pop-lists, except that the list appears under the controlling button rather than on top of it.  The button's label doesn't change and it's marked by a special triangular symbol.  While the choices a user makes in a pop-up list set a state, the choices made in a pull-down list perform actions, much like menu commands.  Before putting a pull-down list in your application, be sure that a menu wouldn't do the job better.  Pull-down lists can be appropriate for actions that are local to a specific area of a panel.  They save screen space and prevent overcrowding in panels.