EntrySet.Lists Namespace
ListBoxDropDown Component
The PureComponents ListBoxDropDown control is used to display data in a drop-down combo box. By default, the ListBoxDropDown control appears in two parts: the top part is a text box that allows the user to type a list item. The second part is a ListBox that displays a list of items from which the user can select one.

ListBoxDropDown is based on a ListBox component therefore the interface is similar. Just the differences are described here, common information you can find in the ListBox chapter.
Popup window has a header at the top which can be turned on and off with the ShowHeader property. The ShowStatus property shows and hides the status bar at the bottom. The text is accessible through HeaderText and StatusText properties. By setting the AllowListResize property to true you can allow the user to resize the popup window.
DropDownShowing and DropDownShow events are raised when opening the popup window.
See also
ListBox Component