diff --git a/src/x11/events.c b/src/x11/events.c
index 18b851c2c..ac4e0059d 100644
--- a/src/x11/events.c
+++ b/src/x11/events.c
@@ -920,35 +920,6 @@ handle_window_focus_event (MetaX11Display *x11_display,
     }
 }
 
-static gboolean
-crossing_serial_is_ignored (MetaX11Display *x11_display,
-                            unsigned long   serial)
-{
-  int i;
-
-  i = 0;
-  while (i < N_IGNORED_CROSSING_SERIALS)
-    {
-      if (x11_display->ignored_crossing_serials[i] == serial)
-        return TRUE;
-      ++i;
-    }
-  return FALSE;
-}
-
-static void
-reset_ignored_crossing_serials (MetaX11Display *x11_display)
-{
-  int i;
-
-  i = 0;
-  while (i < N_IGNORED_CROSSING_SERIALS)
-    {
-      x11_display->ignored_crossing_serials[i] = 0;
-      ++i;
-    }
-}
-
 static gboolean
 handle_input_xevent (MetaX11Display *x11_display,
                      XIEvent        *input_event,
@@ -991,7 +962,7 @@ handle_input_xevent (MetaX11Display *x11_display,
       /* Check if we've entered a window; do this even if window->has_focus to
        * avoid races.
        */
-      if (window && !crossing_serial_is_ignored (x11_display, serial) &&
+      if (window &&
           enter_event->mode != XINotifyGrab &&
           enter_event->mode != XINotifyUngrab &&
           enter_event->detail != XINotifyInferior &&
@@ -1002,12 +973,6 @@ handle_input_xevent (MetaX11Display *x11_display,
                                     enter_event->time,
                                     enter_event->root_x,
                                     enter_event->root_y);
-
-          if (window->type != META_WINDOW_DOCK)
-            {
-              /* stop ignoring stuff */
-              reset_ignored_crossing_serials (x11_display);
-            }
         }
       break;
     case XI_Leave:
diff --git a/src/x11/meta-x11-display-private.h b/src/x11/meta-x11-display-private.h
index 4d06af144..b0ed65ec9 100644
--- a/src/x11/meta-x11-display-private.h
+++ b/src/x11/meta-x11-display-private.h
@@ -37,15 +37,6 @@
 #include "meta-x11-stack-private.h"
 #include "x11/meta-sync-counter.h"
 
-/* This is basically a bogus number, just has to be large enough
- * to handle the expected case of the alt+tab operation, where
- * we want to ignore serials from UnmapNotify on the tab popup,
- * and the LeaveNotify/EnterNotify from the pointer ungrab. It
- * also has to be big enough to hold ignored serials from the point
- * where we reshape the stage to the point where we get events back.
- */
-#define N_IGNORED_CROSSING_SERIALS  10
-
 typedef struct _MetaGroupPropHooks  MetaGroupPropHooks;
 typedef struct _MetaWindowPropHooks MetaWindowPropHooks;
 
@@ -165,12 +156,6 @@ struct _MetaX11Display
 
   guint closing : 1;
 
-  /* serials of leave/unmap events that may
-   * correspond to an enter event we should
-   * ignore
-   */
-  unsigned long ignored_crossing_serials[N_IGNORED_CROSSING_SERIALS];
-
   int composite_event_base;
   int composite_error_base;
   int composite_major_version;
diff --git a/src/x11/meta-x11-display.c b/src/x11/meta-x11-display.c
index d2b260743..4e98203dd 100644
--- a/src/x11/meta-x11-display.c
+++ b/src/x11/meta-x11-display.c
@@ -1294,13 +1294,6 @@ meta_x11_display_new (MetaDisplay  *display,
   x11_display->server_focus_window = None;
   x11_display->server_focus_serial = 0;
 
-  i = 0;
-  while (i < N_IGNORED_CROSSING_SERIALS)
-    {
-      x11_display->ignored_crossing_serials[i] = 0;
-      ++i;
-    }
-
   x11_display->prop_hooks = NULL;
   meta_x11_display_init_window_prop_hooks (x11_display);
   x11_display->group_prop_hooks = NULL;
@@ -2333,29 +2326,6 @@ prefs_changed_callback (MetaPreference pref,
     }
 }
 
-static void
-meta_x11_display_add_ignored_crossing_serial (MetaX11Display *x11_display,
-                                              unsigned long   serial)
-{
-  int i;
-
-  /* don't add the same serial more than once */
-  if (serial ==
-      x11_display->ignored_crossing_serials[N_IGNORED_CROSSING_SERIALS - 1])
-    return;
-
-  /* shift serials to the left */
-  i = 0;
-  while (i < (N_IGNORED_CROSSING_SERIALS - 1))
-    {
-      x11_display->ignored_crossing_serials[i] =
-        x11_display->ignored_crossing_serials[i + 1];
-      ++i;
-    }
-  /* put new one on the end */
-  x11_display->ignored_crossing_serials[i] = serial;
-}
-
 void
 meta_x11_display_set_stage_input_region (MetaX11Display *x11_display,
                                          XserverRegion   region)
@@ -2370,15 +2340,6 @@ meta_x11_display_set_stage_input_region (MetaX11Display *x11_display,
   stage_xwindow = meta_x11_get_stage_window (stage);
   XFixesSetWindowShapeRegion (xdisplay, stage_xwindow,
                               ShapeInput, 0, 0, region);
-
-  /*
-   * It's generally a good heuristic that when a crossing event is generated
-   * because we reshape the overlay, we don't want it to affect
-   * focus-follows-mouse focus - it's not the user doing something, it's the
-   * environment changing under the user.
-   */
-  meta_x11_display_add_ignored_crossing_serial (x11_display,
-                                                XNextRequest (xdisplay));
   XFixesSetWindowShapeRegion (xdisplay,
                               x11_display->composite_overlay_window,
                               ShapeInput, 0, 0, region);