By default, all nodes are expanded. The control fires the Expand event when the user expands or collapses a node.  Use the Expanded property to expand nodes by code. Use the HasButtons property to display the +/- buttons for parent nodes. Use the ExpandOnDblClick property to specify whether a node is expanded or collapsed when the user double clicks it. Use the EnsureVisibleNode method to ensure that a node fits the control's visible client area. Use the SelectNode property to select a node.