Modal GtkMessageDialog on Win32

[asmith15 littlesvr ca]

Here's some code that gives me a modal dialog on Linux but not on Windows:

    GtkWidget* dialog;
    dialog = gtk_message_dialog_new(GTK_WINDOW(GBLmainWindow),
                                           GTK_DIALOG_DESTROY_WITH_PARENT,
                                           GTK_MESSAGE_ERROR,
                                           GTK_BUTTONS_CLOSE,
                                           "asd");
    gtk_dialog_run(GTK_DIALOG(dialog));
    gtk_widget_destroy(dialog);

Here's some sililar code that does give me a modal dialog on Windows
(haven't tried on Linux):

    GtkWidget* dialog;
    dialog = gtk_dialog_new_with_buttons("Warning",
GTK_WINDOW(GBLmainWindow),
                                        GTK_DIALOG_DESTROY_WITH_PARENT,
                                        GTK_STOCK_OK,
                                        GTK_RESPONSE_ACCEPT,
                                        NULL);
    gtk_dialog_run(GTK_DIALOG(dialog));
    gtk_widget_destroy(dialog);

According to the manual the gtk_dialog_run() makes sure the dialog is
modal, but it doesn't for the first case. I tried using
gtk_window_set_modal() and gtk_window_set_transient_for(), didn't help.

Is this a bug in GTK? If so, is it better to wait until it's fixed in GTK
or write my own gtk_message_dialog_new() that just calls
gtk_dialog_new_with_buttons()? Though I'd have to translate the window
title in that case..

Thanks in advance

Andrew