List box

Source: Motif; Windows
Aliases: Selection box; list
Related: Extended selection; multiple selection; single
selection; mouse action
SCO Visual Tcl commands: VtDrawnList*, VtList*

A list box displays objects that users can select. Display each selectable item on a separate line in the list box.

A list box must contain a scroll bar if all objects are not visible and can support either single or multiple selection.

Use list boxes for selection purposes only, not for invoking a command or for navigation.

Main screen lists

Use a list to display objects on the main screen of the application. The general concept is object-action selection where the user selects the list object and then selects the command that acts on that object. (In the case of adding a new object to the list, the object is implied, either exists on media or is created during configuration).

Lists should always appear with an item selected. Null selection in a list should be avoided and considered under special cases only (i.e. the Mover type list). In addition, displaying a highlight gives the user a visual clue that they may select from the list.

Mover/copy lists

These lists move from left to right. The user selects from the list on the left and moves or copies the item to the list on the right.

• The rule of thumb for move versus copy: move the objects from the move-from list into the move-too list. The move-from list loses objects and the move-to list gains objects. Many lists implemented in SCOadmin managers are bi-directional. (The example above is such a list.)

• If the objects in the move-from list are a reference and the objects in that list are not actually removed on the system, then they should remain in the move-from list. However, whenever reasonable, the objects should actually move to the move-too list. This makes scanning easier and more clearly indicates list status. Unless there is overriding reason, use move instead of copy.