Hello Steve
> How can I realize, that when the Cursor is over an TreeNode, that the
> TreeNode will be underlined.
if you mean the text on each node, then it works only with CSS:
----
table tr td a:hover {
text-decoration: underline;
}
----

Signature
Gruss, Peter Bucher
Microsoft MVP - Visual Developer ASP / ASP.NET, Switzerland
http://www.aspnetzone.de/ - ASP.NET Zone, die ASP.NET Community
http://www.aspnetzone.de/blogs/peterbucher/ - Auf den Spuren von .NET