diff --git a/src/core/display.c b/src/core/display.c
index 9be22a4f1..60c3f5fdc 100644
--- a/src/core/display.c
+++ b/src/core/display.c
@@ -1287,38 +1287,6 @@ meta_display_get_current_time_roundtrip (MetaDisplay *display)
     return meta_x11_display_get_current_time_roundtrip (display->x11_display);
 }
 
-/**
- * meta_display_add_ignored_crossing_serial:
- * @display: a #MetaDisplay
- * @serial: the serial to ignore
- *
- * Save the specified serial and ignore crossing events with that
- * serial for the purpose of focus-follows-mouse. This can be used
- * for certain changes to the window hierarchy that we don't want
- * to change the focus window, even if they cause the pointer to
- * end up in a new window.
- */
-void
-meta_display_add_ignored_crossing_serial (MetaDisplay  *display,
-                                          unsigned long serial)
-{
-  int i;
-
-  /* don't add the same serial more than once */
-  if (display->ignored_crossing_serials[N_IGNORED_CROSSING_SERIALS-1] == serial)
-    return;
-
-  /* shift serials to the left */
-  i = 0;
-  while (i < (N_IGNORED_CROSSING_SERIALS - 1))
-    {
-      display->ignored_crossing_serials[i] = display->ignored_crossing_serials[i+1];
-      ++i;
-    }
-  /* put new one on the end */
-  display->ignored_crossing_serials[i] = serial;
-}
-
 static gboolean
 window_raise_with_delay_callback (void *data)
 {
diff --git a/src/meta/display.h b/src/meta/display.h
index 510d802e2..78048e5e2 100644
--- a/src/meta/display.h
+++ b/src/meta/display.h
@@ -168,10 +168,6 @@ META_EXPORT
 GSList *meta_display_sort_windows_by_stacking (MetaDisplay *display,
                                                GSList      *windows);
 
-META_EXPORT
-void meta_display_add_ignored_crossing_serial (MetaDisplay  *display,
-                                               unsigned long serial);
-
 META_EXPORT
 void meta_display_clear_mouse_mode (MetaDisplay *display);
 
diff --git a/src/x11/meta-x11-display.c b/src/x11/meta-x11-display.c
index 222500c84..af26ff1b8 100644
--- a/src/x11/meta-x11-display.c
+++ b/src/x11/meta-x11-display.c
@@ -2381,6 +2381,31 @@ meta_x11_display_focus_sentinel_clear (MetaX11Display *x11_display)
   return (x11_display->sentinel_counter == 0);
 }
 
+
+static void
+meta_x11_display_add_ignored_crossing_serial (MetaX11Display *x11_display,
+                                              unsigned long   serial)
+{
+  MetaDisplay *display = x11_display->display;
+  int i;
+
+  /* don't add the same serial more than once */
+  if (serial ==
+      display->ignored_crossing_serials[N_IGNORED_CROSSING_SERIALS - 1])
+    return;
+
+  /* shift serials to the left */
+  i = 0;
+  while (i < (N_IGNORED_CROSSING_SERIALS - 1))
+    {
+      display->ignored_crossing_serials[i] =
+        display->ignored_crossing_serials[i + 1];
+      ++i;
+    }
+  /* put new one on the end */
+  display->ignored_crossing_serials[i] = serial;
+}
+
 void
 meta_x11_display_set_stage_input_region (MetaX11Display *x11_display,
                                          XserverRegion   region)
@@ -2402,8 +2427,8 @@ meta_x11_display_set_stage_input_region (MetaX11Display *x11_display,
    * focus-follows-mouse focus - it's not the user doing something, it's the
    * environment changing under the user.
    */
-  meta_display_add_ignored_crossing_serial (x11_display->display,
-                                            XNextRequest (xdisplay));
+  meta_x11_display_add_ignored_crossing_serial (x11_display,
+                                                XNextRequest (xdisplay));
   XFixesSetWindowShapeRegion (xdisplay,
                               x11_display->composite_overlay_window,
                               ShapeInput, 0, 0, region);