使用拇指移动变换控件会产生奇怪的行为

I've encountered a weird behavior when trying to use a thumb to move a control around on a canvas. When I add a control to a canvas and use Thumb DragDelta event to move it around everything looks good. But when I apply a rotate transform to the control dragging it around is bizarre. The control starts to circle around the cursor, and the bigger the angle the bigger the circle. I've encountered a weird behavior when trying t