I'm creating a vb.net treeview control to be used in an asp.net page since MS doesn't have an easy way to do that with only asp.net. My question is, after I finish creating the control as a Windows Control Library , I try to add it to my toolbox in order to drag/drop the new control onto my aspx webform, but the icon is grayed out and is inaccessible. If I do the same in a Windows Form application, the control adds just fine. What am I doing that's preventing me from accessing my control on a webform??