To collapse or expand any node with children in a graph, click on the circle alongside it. Thus, click on the unfilled circle of an expandable node to display its children, and click on the filled circle of an expanded node to hide its children.
Figure 6.2 Expanded and expandable nodes
For instance, in Expanded and expandable nodes, click on the unfilled circle alongside CAPI:TOOLBAR-COMPONENT to display its subclasses. Click on the filled circle to hide them.
LispWorks IDE User Guide (Unix version) - 25 Nov 2011