diff --git a/panel/panel-window.c b/panel/panel-window.c
index c21aac36..1d371cad 100644
--- a/panel/panel-window.c
+++ b/panel/panel-window.c
@@ -2013,9 +2013,10 @@ panel_window_screen_layout_changed (GdkScreen   *screen,
         {
           normal_monitor_positioning:
 
+          /* get the primary monitor */
+          monitor_num = gdk_screen_get_primary_monitor (screen);
+
           /* get the monitor geometry based on the panel position */
-          monitor_num = gdk_screen_get_monitor_at_point (screen, window->base_x,
-                                                         window->base_y);
           gdk_screen_get_monitor_geometry (screen, monitor_num, &a);
           panel_return_if_fail (a.width > 0 && a.height > 0);
         }
diff --git a/panel/panel-window.h b/panel/panel-window.h
index f5aa603c..e1de6336 100644
--- a/panel/panel-window.h
+++ b/panel/panel-window.h
@@ -33,6 +33,11 @@ typedef struct _PanelWindow      PanelWindow;
 #define PANEL_IS_WINDOW(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), PANEL_TYPE_WINDOW))
 #define PANEL_IS_WINDOW_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), PANEL_TYPE_WINDOW))
 #define PANEL_WINDOW_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj), PANEL_TYPE_WINDOW, PanelWindowClass))
+/* workaround to get "primary" monitor on gtk versions older than 2.20.0 */
+#if !GTK_CHECK_VERSION (2, 20, 0)
+#define gdk_screen_get_primary_monitor(screen) (gdk_screen_get_monitor_at_point (screen, window->base_x, window->base_y))
+#endif
+
 
 GType      panel_window_get_type                  (void) G_GNUC_CONST;