Custom widget does not get exposed.

["Germán Diago" <germandiago gmail com>]

Hello. I'm doing an application which has a custom widget (derived
from GtkDrawingArea), which goes
inside a derived VBox widget.
The custom widget does custom drawing.
I have a callback which attaches my custom widget to a table and calls
show_all() for the table.
If I attach the custom widget through the callback, when I send to my
widget a signal
related to drawing (when I check a checkbox it is supposed to redraw
with queue_draw()), the expose event is not sent.

If I create in my main function the custom widget, and attach it to
the table before calling
show_all in the main window, things go smoothly, and expose events are
sent for my custom widget. But once the window is shown, if
I attach the widget later, expose events aren't sent for the custom
drawing when I use the checkbox,
which calls queue_draw(). Any idea how to do this correctly? I'm using
gtkmm, but I'm not
getting an answer from its mailing list, and since this is a general
gtk+ problem I think I could ask here.
 Thanks in advance.