diff --git a/gtk/gui_prefs.c b/gtk/gui_prefs.c
index c6af8bd904..a8db02a28a 100644
--- a/gtk/gui_prefs.c
+++ b/gtk/gui_prefs.c
@@ -1,7 +1,7 @@
 /* gui_prefs.c
  * Dialog box for GUI preferences
  *
- * $Id: gui_prefs.c,v 1.20 2000/10/09 06:28:49 guy Exp $
+ * $Id: gui_prefs.c,v 1.21 2000/10/09 06:38:36 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@zing.org>
@@ -320,9 +320,10 @@ font_browse_ok_cb(GtkWidget *w, GtkFontSelectionDialog *fs)
 	font_name = g_strdup(gtk_font_selection_dialog_get_font_name(
 	      GTK_FONT_SELECTION_DIALOG(fs)));
 	if (font_name == NULL) {
-		/* No font was selected; let the user know, and don't let
-		   them accept that non-font. */
-		simple_dialog(ESD_TYPE_CRIT, NULL,
+		/* No font was selected; let the user know, but don't
+		   tear down the font selection dialog, so they can
+		   try again. */
+		simple_dialog(ESD_TYPE_CRIT | ESD_TYPE_MODAL, NULL,
 		   "You have not selected a font.");
 		return;
 	}
@@ -336,7 +337,7 @@ font_browse_ok_cb(GtkWidget *w, GtkFontSelectionDialog *fs)
 		/* Oops, that font didn't work.
 		   Tell the user, but don't tear down the font selection
 		   dialog, so that they can try again. */
-		simple_dialog(ESD_TYPE_CRIT, NULL,
+		simple_dialog(ESD_TYPE_CRIT | ESD_TYPE_MODAL, NULL,
 		   "The font you selected cannot be loaded.");
 
 		g_free(font_name);
@@ -349,7 +350,7 @@ font_browse_ok_cb(GtkWidget *w, GtkFontSelectionDialog *fs)
 		/* Oops, that font didn't work.
 		   Tell the user, but don't tear down the font selection
 		   dialog, so that they can try again. */
-		simple_dialog(ESD_TYPE_CRIT, NULL,
+		simple_dialog(ESD_TYPE_CRIT | ESD_TYPE_MODAL, NULL,
 		   "The font you selected doesn't have a boldface version.");
 
 		g_free(font_name);
diff --git a/gtk/simple_dialog.c b/gtk/simple_dialog.c
index 61269534a2..d0377422d0 100644
--- a/gtk/simple_dialog.c
+++ b/gtk/simple_dialog.c
@@ -1,7 +1,7 @@
 /* simple_dialog.c
  * Simple message dialog box routines.
  *
- * $Id: simple_dialog.c,v 1.6 2000/08/23 06:56:31 guy Exp $
+ * $Id: simple_dialog.c,v 1.7 2000/10/09 06:38:36 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@zing.org>
@@ -76,7 +76,7 @@ simple_dialog(gint type, gint *btn_mask, gchar *msg_format, ...) {
   gchar      **icon;
 
   /* Main window */
-  switch (type) {
+  switch (type & ~ESD_TYPE_MODAL) {
   case ESD_TYPE_WARN :
     icon = icon_excl_xpm;
     win = dlg_window_new("Ethereal: Warning");
@@ -92,6 +92,9 @@ simple_dialog(gint type, gint *btn_mask, gchar *msg_format, ...) {
     break;
   }
 
+  if (type & ESD_TYPE_MODAL)
+    gtk_window_set_modal(GTK_WINDOW(win), TRUE);
+
   gtk_container_border_width(GTK_CONTAINER(win), 7);
 
   gtk_object_set_data(GTK_OBJECT(win), bm_key, btn_mask);
diff --git a/simple_dialog.h b/simple_dialog.h
index 9afdf1f1e5..f952c19940 100644
--- a/simple_dialog.h
+++ b/simple_dialog.h
@@ -2,7 +2,7 @@
  * Definitions for dialog box routines with toolkit-independent APIs but
  * toolkit-dependent implementations.
  *
- * $Id: simple_dialog.h,v 1.1 2000/01/03 06:59:09 guy Exp $
+ * $Id: simple_dialog.h,v 1.2 2000/10/09 06:38:34 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@zing.org>
@@ -32,9 +32,13 @@ extern "C" {
 #endif /* __cplusplus */
 
 /* Dialog type. */
-#define ESD_TYPE_INFO 0
-#define ESD_TYPE_WARN 1
-#define ESD_TYPE_CRIT 2
+#define ESD_TYPE_INFO	0x00
+#define ESD_TYPE_WARN	0x01
+#define ESD_TYPE_CRIT	0x02
+
+/* Flag to be ORed with the dialog type, to specify that the dialog is
+   to be modal. */
+#define ESD_TYPE_MODAL	0x04
 
 /* Which buttons to display. */
 #define ESD_BTN_OK     0