I noticed a peculiarity in the dieView dragging behavior. If I dragged a die image to an “invalid” drop location (like the menu bar), the zoom-back animation would sometimes end in the wrong place. After a little investigating, I found that the offset was caused by the drag image being centered under the mouse, even when the initial mouseDown was off-center.
I fixed it by changing a line in mouseDragged. Instead of offsetting the draggingFrame by half of the image width (& height), I offset it by the draggingFrameOrigin.