It seems Webkit does not honor cursor hotspot (the pixel where when the mouse button is clicked that corresponds to where exactly the cursor's click is being directed). My site has an example with DHTML enabled (jQuery), custom cursors enabled, and a prompt loaded automatically (Basic Options). Simply move the mouse cursor over the top header and the cursor will change visually suggesting that you can click, hold, and move the prompt (layer) around like a window. However the hotspot on the cursor is directly in the middle however Webkit seems to presume it is at the top.
This site uses .cur cursors, so it's a duplicate of bug 15779. *** This bug has been marked as a duplicate of 15779 ***