Basically it is my "Dim WithEvents App as Visio.Application". Then I watch the selectionchanged event from the visio app but in the eventhandler sub, i try to loop through my treenodes on my treeview and I get the error where I cannot manipulate items on the main thread, or whatever you get along those lines. After that I tried to create an event on myu main form that fired when the selectionchanged on the visio application, basically it was a double event fire, in hopes of having the event fire on the main thread but I get same results.

Any thoughts?