Common Desktop Environment: Style Guide and Certification Checklist

Selection

The desktop has incorporated two significant changes to selection in Motif. The first is that users may elect to have either Adjust or Transfer capability on the middle mouse button. In addition, the desktop integrates drag and select on the first mouse button.

On a three-button mouse, button 2 is typically used for the BTransfer (or BSelect) function. However, in a Common Desktop Environment environment, the user may change an environment setting indicating that mouse button 2 should be used for the BAdjust function instead. BAdjust can be used to toggle the selection state of elements under the multiple selection model.

The following guidelines describe the BAdjust behaviors.

Mouse-Based Multiple Selection

Required	i:	If your application contains collections that follow the multiple selection model, BAdjust is supported and behaves just like BSelect, when the BTransfer button is currently configured to behave as BAdjust.
Required	j:	In a collection that uses multiple selection, clicking BSelect or BAdjust on an unselected element adds that element to the current selection. Clicking BSelect or BAdjust on a selected element removes that element from the current selection. Clicking BSelect or BAdjust moves the location cursor to that element.

Mouse-Based Range Selection

Required	m:	If your application contains collections that follow the range selection model, BAdjust is supported and behaves just like Shift+BSelect, when the BTransfer button is currently configured to behave as BAdjust.
Required	n:
		Reselect	The extended range is determined by the anchor and the current pointer position, in exactly the same manner as when the selection was initially made.
		Enlarge Only	The selection can only be enlarged. The extended range is determined by the anchor and the current pointer position, but then is enlarged to include the current selection.
		Balance Beam	A balance point is defined at the midpoint of the current selection. When the user presses Shift+BSelect or BAdjust on the opposite side of the balance point from the anchor, this model works exactly like the reselect model. When the user presses Shift+BSelect, BAdjust, or starts a navigation action modified by Shift on the same side of the balance point as the anchor, this model moves the anchor to the opposite end of the selection and then works exactly like the reselect model.
		When the user releases BSelect or BAdjust, the anchor does not move, all the elements within the extended range are selected, and all the elements outside of it are deselected.

Mouse-Based Discontiguous Selection

Required

In a collection that uses discontiguous selection, BAdjust can be used to extend the range of a discontiguous selection. The extended range is determined in exactly the same way as when BAdjust is used to extend a range selection.