The Adorner is only visible when effects != none AND dragsource does also accept drops.

I don't know about the window guidelines, but I like that the Adorner is always visible (even if the source doesn't accept drops).

I did accomplish this in two ways: 1. Let the source also accept drops. Create a class ListViewDropHandler : IDropTarget that always returns Effects.None at dragover 2. Change DropTarget_PreviewDragOver in dragdrop.cs. Comment the line "if (dropInfo.Effects != DragDropEffects.None)" and remove the else part.

I came up with this idea as it is a bit strange that when you start dragging you only see the "forbidden sign" and when a drag is allowed you'll see the adorner with the "copy sign".

What do you think about this?