Button remains "pressed" until callback function ends

[Michal Kepien <lordpopcorn poczta onet pl>]

Hi, I'm quite a newbie to GTK+ and got some trouble with handling button clicks.
I've got a callback function which reads in and plays a sound file. This
function is connected to the "clicked" event of a button. The problem is, the
button stays "pushed" until the sound playing function finishes its work. I want
the button to pop out immediately after it has been clicked (and of course, the
callback function to play the sound anyway). Is there any way to achieve that?
I've tried to understand the code of some applications which implement such a
feature, but haven't found out anything worth mentioning...

Thanks in advance for any support,
Michal Kepien