y 

n/a 

n 

Required 

_ 

_ 

_ 

4-9: 

In a collection that uses discontiguous selection, the behavior of BSelect is exactly the same as in the range selection model. After the user sets the anchor with BSelect, Shift+BSelect works exactly as in the range selection model. 

Discontiguous selection is an extension of range selection that allows the user to select multiple discontiguous ranges of elements. 

Required 

_ 

_ 

_ 

4-10: 

In a collection that uses discontiguous selection, when the current selection is not empty and the user clicks Control+BSelect, the anchor and location cursor move to that point. If the current selection is not empty and the user clicks Control+BSelect on an element, the selection state of that element is toggled, and that element becomes the anchor element. 

In discontiguous selection, Control+BSelect Click provides a convenient means of moving the anchor and toggling the selection state of the element under the pointer. 

Required 

_ 

_ 

_ 

4-11: 

In a collection that uses discontiguous selection, Control+BSelect Motion toggles the selection state of a range of elements. The range itself is determined exactly as for BSelect Motion. Releasing Control+BSelect toggles the selection state of the elements in the range according to one of two models: 

Anchor Toggle 

Toggling is based on an anchor element. If the range is anchored by a point, and is not empty, the anchor element is set to the element within the range that is nearest to the anchor point. Toggling sets the selection state of all elements in the range to the inverse of the initial state of the anchor element. 

Full Toggle 

The selection state of each element in the extended range is toggled. 

In discontiguous selection, Control+BSelect provides a convenient means of toggling the selection state of elements in a range. 

Required 

_ 

_ 

_ 

4-12: 

In a collection that uses discontiguous selection, after Control+BSelect toggles a selection, Shift+BSelect or Control+Shift+BSelect extends the range of toggled elements. The extended range is determined in exactly the same way as when Shift BSelect is used to extend a range selection. When the user releases Control+Shift+BSelect, the selection state of elements added to the range is determined by the toggle model in use (either Anchor Toggle or Full Toggle). If elements are removed from the range, they either revert to their state prior to the last use of Control+BSelect or change to the state opposite that of the elements remaining within the extended range.  

Shift+BSelect and Control+Shift+BSelect provide a convenient means of extending the range of toggled elements. 

Required 

_ 

_ 

_ 

o: 

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. 

On a three-button mouse, mouse button 2 is typically used for the BTransfer 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 extend the selection set in the same manner as Shift+BSelect.