motion events

[Nick Soffe <nick soffe bioch ox ac uk>]

Hi,
I have a drawing area in which I can place two vertical lines (used as
cursors) using mouse buttons 1+2. The cursors can  be moved around from
mouse motion events whilst holding down a button.
I have set GDK_BUTTON_PRESS_MASK and GDK_POINTER_MOTION_MASK on the
drawing area and connected 'motion_notify_event' and 'button_press_event'
to my callbacks. Tested individually the button press and motion events
are only detected whilst the pointer is in the drawing area as I would
expect. With any button pressed however motion events continue to
be produced when the pointer leaves the drawingarea. This also occurs
with a similar routine in the "scribble" example under either gtk1.2 or
gtk2.0 so seems to be  expected behaviour. This isn't a problem but I am
curious to know why this occurs. Sorry if this is obvious I'm new to all
this.
Nick Soffe.