Dragging in UI
When the user drags an item to a location, slows movement, and then makes a quick movement right before finishing the drag, the user probably wanted the ending location to be the mouse location right before the quick movement. The user should be prompted for which target they want if the quick movement changed the target. With normal mice there probably isn't often a quick movement but I use a pen (an old version of the Intuos 6x8) for ergonomic reasons and I often have a quick movement as I let go of the button on the pen.
Also when I drag from one program to another (i.e. Drag a file from Explorer to my editor) I expect the drag recipient to receive focus. I constantly press a hotkey thinking my editor has focus when explorer still has focus.
I admit that pens aren't very common so most people probably don't have that problem but do you agree that focus should move to the drag target?