No, i am not adding them at runtime.
My main app has a canvas and i add the usercontrol directly to the canvas and then drag the object behaviour onto the user control.
If i drag the object behaviour onto something else on my canvas like a button or a rectangle the project runs fine, but when i drag it onto the usercontrol the project loads and then crashes instantly....
The porect is pretty big so if i pasted it here it would take up a few pages.... I could always post snippets...