21.7.8 Motion Events

Emacs sometimes generates mouse motion events to describe motion of the mouse without any button activity. Mouse motion events are represented by lists that look like this:

     (mouse-movement POSITION)

position is a mouse position list (see Click Events), specifying the current position of the mouse cursor. As with the end-position of a drag event, this position list may represent a location outside the boundaries of the initially selected frame, in which case the list contains that frame in place of a window.

The special form track-mouse enables generation of motion events within its body. Outside of track-mouse forms, Emacs does not generate events for mere motion of the mouse, and these events do not appear. See Mouse Tracking.