diff --git a/ChangeLog b/ChangeLog
index 685faabf0eed1ced9e8e81e5f344b4da40dad36e..0fc7118e286f4feae8e1fdab607201f5969a67ca 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2005-11-21  Sven Neumann  <sven@gimp.org>
+
+	* plug-ins/MapObject/mapobject_main.[ch]
+	* plug-ins/MapObject/mapobject_preview.c
+	* plug-ins/MapObject/mapobject_ui.c: must not keep pointers in the
+	struct that is being used to preserve data between invocations of
+	the plug-in. Fixes bug #321932.
+
 2005-11-19  Michael Natterer  <mitch@gimp.org>
 
 	* app/tools/gimppaintoptions-gui.c
diff --git a/plug-ins/MapObject/mapobject_main.c b/plug-ins/MapObject/mapobject_main.c
index 69198e101ff8704c606c0bf8df0c50cf76597865..ad345ea3a0dfd39394e9fe832a990501c817a254 100644
--- a/plug-ins/MapObject/mapobject_main.c
+++ b/plug-ins/MapObject/mapobject_main.c
@@ -74,9 +74,7 @@ set_default_settings (void)
   mapvals.cylinder_radius = 0.25;
   mapvals.cylinder_length = 1.0;
 
-  mapvals.zoom_model = gimp_zoom_model_new ();
-  gimp_zoom_model_set_range (mapvals.zoom_model, 0.25, 1.0);
-
+  mapvals.zoom             = 1.0;
   mapvals.lightsource.type = POINT_LIGHT;
 
   mapvals.antialiasing           = TRUE;
diff --git a/plug-ins/MapObject/mapobject_main.h b/plug-ins/MapObject/mapobject_main.h
index b879df10cfb61c851e35c0845ad3a90cb1a48210..cfd8ca716c8738aafeef1b1f832dbfbb996143f9 100644
--- a/plug-ins/MapObject/mapobject_main.h
+++ b/plug-ins/MapObject/mapobject_main.h
@@ -63,8 +63,7 @@ typedef struct
   gint showgrid;
   gint showcaps;
 
-  GimpZoomModel *zoom_model;
-
+  gdouble zoom;
   gdouble alpha,beta,gamma;
   gdouble maxdepth;
   gdouble pixeltreshold;
diff --git a/plug-ins/MapObject/mapobject_preview.c b/plug-ins/MapObject/mapobject_preview.c
index cdc003089582a479e7844aaded44a67cf751a7ad..0ddec02e1ecf7999da223b324b35c202d0aaad43 100644
--- a/plug-ins/MapObject/mapobject_preview.c
+++ b/plug-ins/MapObject/mapobject_preview.c
@@ -396,10 +396,9 @@ update_light (gint xpos,
 	      gint ypos)
 {
   gint    startx, starty, pw, ph;
-  gdouble zoom = gimp_zoom_model_get_factor (mapvals.zoom_model);
 
-  pw     = PREVIEW_WIDTH * zoom;
-  ph     = PREVIEW_HEIGHT * zoom;
+  pw     = PREVIEW_WIDTH * mapvals.zoom;
+  ph     = PREVIEW_HEIGHT * mapvals.zoom;
   startx = (PREVIEW_WIDTH  - pw) / 2;
   starty = (PREVIEW_HEIGHT - ph) / 2;
 
@@ -416,7 +415,6 @@ void
 draw_preview_image (gint docompute)
 {
   gint startx, starty, pw, ph;
-  gdouble   zoom;
   GdkColor  color;
 
   color.red   = 0x0;
@@ -432,10 +430,8 @@ draw_preview_image (gint docompute)
   gdk_gc_set_function (gc, GDK_COPY);
   linetab[0].x1 = -1;
 
-  zoom = gimp_zoom_model_get_factor (mapvals.zoom_model);
-
-  pw = PREVIEW_WIDTH * zoom;
-  ph = PREVIEW_HEIGHT * zoom;
+  pw = PREVIEW_WIDTH * mapvals.zoom;
+  ph = PREVIEW_HEIGHT * mapvals.zoom;
   startx = (PREVIEW_WIDTH - pw) / 2;
   starty = (PREVIEW_HEIGHT - ph) / 2;
 
@@ -475,8 +471,7 @@ draw_preview_image (gint docompute)
 void
 draw_preview_wireframe (void)
 {
-  gint startx, starty, pw, ph;
-  gdouble   zoom;
+  gint      startx, starty, pw, ph;
   GdkColor  color;
 
   color.red   = 0x0;
@@ -491,10 +486,8 @@ draw_preview_wireframe (void)
 
   gdk_gc_set_function (gc, GDK_INVERT);
 
-  zoom = gimp_zoom_model_get_factor (mapvals.zoom_model);
-
-  pw     = PREVIEW_WIDTH  * zoom;
-  ph     = PREVIEW_HEIGHT * zoom;
+  pw     = PREVIEW_WIDTH  * mapvals.zoom;
+  ph     = PREVIEW_HEIGHT * mapvals.zoom;
   startx = (PREVIEW_WIDTH  - pw) / 2;
   starty = (PREVIEW_HEIGHT - ph) / 2;
 
diff --git a/plug-ins/MapObject/mapobject_ui.c b/plug-ins/MapObject/mapobject_ui.c
index ace33548257bf67da253c878b3d682c8d52721ed..d17601798e155b63e4d93ca5d2e3f0173b848a13 100644
--- a/plug-ins/MapObject/mapobject_ui.c
+++ b/plug-ins/MapObject/mapobject_ui.c
@@ -300,10 +300,13 @@ preview_callback (GtkWidget *widget,
 }
 
 static void
-zoom_notify_callback (GObject *model)
+zoomed_callback (GimpZoomModel *model)
 {
+  mapvals.zoom = gimp_zoom_model_get_factor (model);
+
   if (linetab[0].x1 != -1)
     clear_wireframe ();
+
   draw_preview_image (TRUE);
 }
 
@@ -1330,13 +1333,14 @@ create_main_notebook (GtkWidget *container)
 gboolean
 main_dialog (GimpDrawable *drawable)
 {
-  GtkWidget *main_hbox;
-  GtkWidget *vbox;
-  GtkWidget *hbox;
-  GtkWidget *frame;
-  GtkWidget *button;
-  GtkWidget *toggle;
-  gboolean   run = FALSE;
+  GtkWidget     *main_hbox;
+  GtkWidget     *vbox;
+  GtkWidget     *hbox;
+  GtkWidget     *frame;
+  GtkWidget     *button;
+  GtkWidget     *toggle;
+  GimpZoomModel *model;
+  gboolean       run = FALSE;
 
   gimp_ui_init ("MapObject", FALSE);
 
@@ -1404,18 +1408,20 @@ main_dialog (GimpDrawable *drawable)
 
   gimp_help_set_help_data (button, _("Recompute preview image"), NULL);
 
-  button = gimp_zoom_button_new (mapvals.zoom_model,
-                                 GIMP_ZOOM_IN, GTK_ICON_SIZE_MENU);
+  model = gimp_zoom_model_new ();
+  gimp_zoom_model_set_range (model, 0.25, 1.0);
+  gimp_zoom_model_zoom (model, GIMP_ZOOM_TO, mapvals.zoom);
+
+  button = gimp_zoom_button_new (model, GIMP_ZOOM_IN, GTK_ICON_SIZE_MENU);
   gtk_box_pack_end (GTK_BOX (hbox), button, FALSE, FALSE, 0);
   gtk_widget_show (button);
 
-  button = gimp_zoom_button_new (mapvals.zoom_model,
-                                 GIMP_ZOOM_OUT, GTK_ICON_SIZE_MENU);
+  button = gimp_zoom_button_new (model, GIMP_ZOOM_OUT, GTK_ICON_SIZE_MENU);
   gtk_box_pack_end (GTK_BOX (hbox), button, FALSE, FALSE, 0);
   gtk_widget_show (button);
 
-  g_signal_connect (mapvals.zoom_model, "notify::value",
-                    G_CALLBACK (zoom_notify_callback),
+  g_signal_connect (model, "zoomed",
+                    G_CALLBACK (zoomed_callback),
                     NULL);
 
   toggle = gtk_check_button_new_with_mnemonic (_("Show preview _wireframe"));