size of file select dialog

[brent verner <damonbrent earthlink net>]

oh, gui gurus,

i've tried gdk_window_get_size on a file select dialog, but
it doesn't seem to work.

fsd = gtk_file_selection_new( (const gchar *)title );
gdk_window_get_size( fsd->window, &x_fsd, & y_fsd );

what am i missing here?
i've tried showing/realizing the window before trying to get
its size, but neither makes this work. tried casting  fsd
to (u_name_it *) as well...

any suggestions?

thnks.
brent