pointer grabs and drawing areas

[Paul Davis <pbd op net>]

i have a drawing area set up to receive both button press+release
events. my understanding is that X/GDK automatically does a pointer
grab when a GdkWindow has these events set for itself. i also receive
motion events, via motion hints.

if i press and then move the pointer outside the drawing area, i
continue to get motion events. however, this is only true if i don't
move the pointer into the canvas that is packed above the drawing area
in a table. 

how could this be? can the canvas grab the pointer away somehow?

--p