Treeview SelectedNodeChanged event not firing

Ref: (http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.treenode.aspx)

Ref: (http://www.codenewsgroups.net/group/microsoft.public.dotnet.framework.aspnet.webcontrols/topic9080.aspx)

The text of a node in the TreeView control can be in one of two modes: selection mode or navigation mode. By default, a node is in selection mode. To put a node into navigation mode, set the node's NavigateUrl property to a value other than an empty string (""). To put a node into selection mode, set the node's NavigateUrl property to an empty string.

By default, clicking a node that is in selection mode posts the page back to the server and raises the SelectedNodeChanged event. You can optionally specify a different event to raise by setting the node's SelectAction property. For more information, see SelectAction. To determine which node was clicked in selection mode, use the SelectedNode property of the TreeView control.