>Barbara,
>
>I put OutputDebugString() calls in DragOver to display the value of x and y being passed in while I dragged the mouse around the TreeView window. I noticed that when I was at the left edge of the window the value was not zero, but was actually the value of the Left property of the TreeView control. Also, when the mouse was on the right edge of the window, the value of x being passed in was Left+Width. Similarly for the vertical dimension.
>
>Have you looked at the values actually being passed in to DragOver?
>
>Jim

No, I haven't looked at what's in the X and Y parameters, because the code I used worked fine. I didn't need to start debugging.