Index: gtk/gtkmessagedialog.c
===================================================================
--- gtk/gtkmessagedialog.c	(revision 21809)
+++ gtk/gtkmessagedialog.c	(working copy)
@@ -74,7 +74,8 @@
   PROP_USE_MARKUP,
   PROP_SECONDARY_TEXT,
   PROP_SECONDARY_USE_MARKUP,
-  PROP_IMAGE
+  PROP_IMAGE,
+  PROP_WRAP_MODE
 };
 
 G_DEFINE_TYPE (GtkMessageDialog, gtk_message_dialog, GTK_TYPE_DIALOG)
@@ -217,6 +218,22 @@
                                                         GTK_TYPE_WIDGET,
                                                         GTK_PARAM_READWRITE));
 
+  /**
+   * GtkMessageDialog:wrap-mode:
+   *
+   * This controls how the line wrapping is done. The default is
+   * %PANGO_WRAP_WORD which means wrap on word boundaries.
+   *
+   * Since: 2.16
+   */
+  g_object_class_install_property (gobject_class,
+                                   PROP_WRAP_MODE,
+                                   g_param_spec_enum ("wrap-mode",
+                                                      P_("Line wrap mode"),
+                                                      P_("Controls how linewrapping is done"),
+                                                      PANGO_TYPE_WRAP_MODE,
+                                                      PANGO_WRAP_WORD,
+                                                      GTK_PARAM_READWRITE));
   g_type_class_add_private (gobject_class,
 			    sizeof (GtkMessageDialogPrivate));
 }
@@ -420,6 +437,9 @@
     case PROP_IMAGE:
       gtk_message_dialog_set_image (dialog, g_value_get_object (value));
       break;
+    case PROP_WRAP_MODE:
+      gtk_message_dialog_set_line_wrap_mode (dialog, g_value_get_enum (value));
+      break;
 
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
@@ -467,6 +487,10 @@
     case PROP_IMAGE:
       g_value_set_object (value, dialog->image);
       break;
+    case PROP_WRAP_MODE:
+      g_value_set_enum (value, gtk_message_dialog_get_line_wrap_mode (dialog));
+      break;
+
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -742,6 +766,52 @@
 }
 
 /**
+ * gtk_message_dialog_set_line_wrap_mode:
+ * @dialog: a #GtkMessageDialog
+ * @wrap: the line wrapping mode
+ *
+ * This controls how the line wrapping of @dialog's labels is done.
+ * The default is %PANGO_WRAP_WORD which means to wrap on word boundaries.
+ *
+ * Since: 2.16
+ **/
+void
+gtk_message_dialog_set_line_wrap_mode (GtkMessageDialog *dialog,
+				       PangoWrapMode     mode)
+{
+  GtkMessageDialogPrivate *priv;
+
+  g_return_if_fail (GTK_IS_MESSAGE_DIALOG (dialog));
+
+  priv = GTK_MESSAGE_DIALOG_GET_PRIVATE (dialog);
+  gtk_label_set_line_wrap_mode (GTK_LABEL (dialog->label), mode);
+  gtk_label_set_line_wrap_mode (GTK_LABEL (priv->secondary_label), mode);
+
+  g_object_notify (G_OBJECT (dialog), "wrap-mode");
+}
+
+/**
+ * gtk_message_dialog_get_line_wrap_mode:
+ * @dialog: a #GtkMessageDialog
+ *
+ * Gets the line wrapping mode of the @dialog's labels.
+ 
+ * Return value: the line wrapping mode
+ *
+ * Since: 2.16
+ **/
+PangoWrapMode
+gtk_message_dialog_get_line_wrap_mode (GtkMessageDialog *dialog)
+{
+  g_return_if_fail (GTK_IS_MESSAGE_DIALOG (dialog));
+
+  /* Note that the line wrap property will get out of sync if someone
+     manually sets it on a label by traversing the widget
+     hierarchy. */
+  return gtk_label_get_line_wrap_mode (GTK_LABEL (dialog->label));
+}
+
+/**
  * gtk_message_dialog_format_secondary_markup:
  * @message_dialog: a #GtkMessageDialog
  * @message_format: printf()-style markup string (see 
Index: gtk/gtkmessagedialog.h
===================================================================
--- gtk/gtkmessagedialog.h	(revision 21809)
+++ gtk/gtkmessagedialog.h	(working copy)
@@ -116,6 +116,9 @@
 void       gtk_message_dialog_format_secondary_markup (GtkMessageDialog *message_dialog,
                                                        const gchar      *message_format,
                                                        ...) G_GNUC_PRINTF (2, 3);
+void       gtk_message_dialog_set_line_wrap_mode (GtkMessageDialog *dialog,
+                                                  PangoWrapMode     mode);
+PangoWrapMode gtk_message_dialog_get_line_wrap_mode (GtkMessageDialog *dialog);
 
 G_END_DECLS
 
Index: gtk/gtk.symbols
===================================================================
--- gtk/gtk.symbols	(revision 21809)
+++ gtk/gtk.symbols	(working copy)
@@ -2446,6 +2446,8 @@
 gtk_message_dialog_set_markup
 gtk_message_dialog_set_image
 gtk_message_dialog_get_image
+gtk_message_dialog_set_line_wrap_mode
+gtk_message_dialog_get_line_wrap_mode
 #endif
 #endif
 
