gdk-window-event-compression (window)

window -- a gdk-window object
event-compression -- a true if motion events will be compressed

Determines whether or not extra unprocessed motion events in the event queue can be discarded. If true only the most recent event will be delivered.

Some types of applications, e.g. paint programs, need to see all motion events and will benefit from turning off event compression. By default, event compression is enabled.