It is already explicitly assumed that anonymous authentication will
be used when available, but it is not clear to the user since neither
of the check buttons are selected. Select the Anonymous check button
by default.
gtk_grid_attach (GTK_GRID (grid), anon_box, 1, rows++, 1, 1);
choice = gtk_check_button_new_with_mnemonic (_("_Anonymous"));
+ gtk_check_button_set_active (GTK_CHECK_BUTTON (choice), TRUE);
gtk_box_append (GTK_BOX (anon_box), choice);
g_signal_connect (choice, "toggled",
G_CALLBACK (pw_dialog_anonymous_toggled), operation);