Option panes, created with the
class, display the current selection from a single-selection list. When you click on the option pane, the list appears and you can make another selection from it. Once the selection is made, it is displayed in the option pane.
The appearance of the
list varies between platforms. a drop-down list box on Microsoft Windows; a combo box on GTK+ or Motif, and a popup list on Cocoa.
Here is an example option pane, which shows the choice of one of five numbers. The initial selection is controlled with
:items '(1 2 3 4 5)
:title "One of Five:"))
Figure 6.8 An option pane
CAPI User Guide (Windows version) - 30 Aug 2011