All the children of the selected node also change color. A singular node indicates that only one logical node is associated with that visual object. An overloaded node indicates more than one logical node is associated with that visual object. An unused node is a node which is not part of the current selected hierarchy. There are no unused nodes when the root is selected.
Nodes become unused only when the user starts to descend down the hierarchy.
When a hierarchy is initially displayed, the complete hierarchy is shown. When a visual component, other than the root node, is selected, the hierarchy associated with this selected node is displayed. Any visual components that are not within the selected hierarchy will be set to the unused state. The border of the visual components is used to indicate the focus point. When the cursor is moved into a visual component, the components that are being browsed are highlighted.