Newbie question: gtk_widget_destroy()

[Lucia <luccia adinet com uy>]

How can I destroy a window, without destroying the main window?  

For example, in a file selection widget, when the Cancel button is pressed I 
connect like this:
g_signal_connect(G_OBJECT(GTK_FILE_SELECTION(file_widget)->cancel_button), 
"clicked", GTK_SIGNAL_FUNC(gtk_widget_destroy), G_OBJECT(file_widget));

Thank you,

Lucia.