Weird behavior of Drag Adorner when dragging to window border

[nimnes]

Steps to reproduce

1. Use test XAML instead of Window.xaml in DefaultsExample project in gong-wpf-dragdrop repo.
2. Drag item to left window border (first pixel after window border actually).

Drag Adorner will moving up continuously screenshot.

Possible way to fix:
change DragDrop.cs

line 791    if (tempAdornerPos.X > 0 && tempAdornerPos.Y > 0) {

to

line 791    if (tempAdornerPos.X >= 0 && tempAdornerPos.Y >= 0) {