Allan,

>Is there any way to 'pop-up' a 4 column 'header' at the correct position above the combo box when it opens? I realize that I won't know the exact position of the combo box or the contents of the header until runtime.

I think I'd lay out the labels before hand in the designer and just control their .Visible property based on the value of the first cbo and the second's DropDown event.