Which signal should I catch?

[Chen Gang <c-g03 mails tsinghua edu cn>]

Hi.

I'm learning Gtk application programming.  I want to write an application
from the example shipped with gtk, "scribble-simple".  I found the
backing pixmap of the drawing area widget would never be destroyed, so I
want to destroy it whenever the X window of the drawing area widget is
changed or destroyed.  Then which signal should I catch?  That is, which
signal will be emitted when the X window of a widget is changed or
destroyed?

BTW, I found little knowledge of the meaning of each Gtk signals in the
Gtk Reference Manual.

Sorry for my poor English.

Thanks very much!


Chen