The hot spot of the cursor is the location in the cursor bitmap that is tracked and recognized as the position of the mouse or keyboard arrow key. For example, the hot spot on the pointer is the point at the tip of the arrow.
The ClipCursor function confines the cursor to a given rectangle on the screen. The cursor can move to the edge of the rectangle but cannot move out of it. ClipCursor is typically used to restrict the cursor to a given window, such as a dialog box that contains a warning about a serious error. The rectangle is always given in screen coordinates and does not have to be within the window of the active application.