Using thumb to move transformed control produces weird behavior

Question

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.

Does anyone know how to make thumb work with a transformed element? I've spent all day trying to figure it out and nothing smart is coming to my mind.

Thanks for your help!

Answer 1

It appears that Thumb's HorizontalChange and VerticalChange don't play nicely when thumb is rotated. So, I'm just using cursor location in the canvas get my left and top offsets. Its not exactly accurate, but its close enough for what I'm trying to do.