It's right, I didn't explain it clearly...:
I want to make the real transparency, when a Label is over a PictureBox we'll can see the PictureBox on the label, The only way I found is to draw this PictureBox on the background (not set it as background just draw it with the same dimension and position) but on this Form there's several PictureBox and I would like when I change the PictureBox position just redraw it but lets the others and refresh the Label who is over this PictureBox...
If it's not understable yet I'll can explain more clearly again...
Thanks for your reply!