4.2 List panels

4.2.2 Extended selection

Application users often want to make single and multiple selections from a list. Some of the time they want a new selection to deselect the previous one, so that only one selection remains -- just like a:single-selection panel. On other occasions, they want new selections to be added to the previous ones -- just like a:multiple-selection panel.

The:extended-selection interaction combines these two interactions. Here is an extended-selection list panel:

(contain
 (make-instance 
  'list-panel
  :items '("Item" "Thing" "Object")
  :interaction :extended-selection))

Before continuing, here are the definitions of a few terms. The action you perform to select a single item is called the selection gesture. The action performed to select additional items is called the extension gesture. There are two extension gestures. To add a single item to the selection, the extension gesture is a click of the left button while holding down the Control key. For selecting a range of items, it is a click of the left button whilst holding down the Shift key.

CAPI User Guide, Liquid Common Lisp Version 5.0 - 2 OCT 1997

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