program handling mouse's "button release" event

[huzheng <forlinux 263 net>]

i create a eventbox,and make a pixmap widget in it.
then use 
"gtk_signal_connect" to connect  "button_press_event" and
"button_release_event" to the eventbox
when i receive "button_press_event", i set the pixmap widget's pixmap to
a mousedown pixmap,and when receive the "button_release_event",i change
the pixmap widget's pixmap to normal pixmap.
but i get some program when handling the "button_release_event".

if the main window have a event_box_1,and a dialog window have a event
box_2.i use gtk_window_set_modal (GTK_WINDOW (window), TRUE); to make
the dialog be modal,then when i press mouse on event_box2,and release
mouse on event_box_1, both event_box_1 and event_box_2 can't get the
button release event.the release event just lost....how should i solve
this program?

many thanks to any reply! :)