diff --git a/js/ui/windowmanager.js b/js/ui/windowmanager.js
index d143efe14..83dde3d5b 100644
--- a/js/ui/windowmanager.js
+++ b/js/ui/windowmanager.js
@@ -1,29 +1,125 @@
-/* -*- mode: js2; js2-basic-offset: 4; -*- */
+/* -*- mode: js2; js2-basic-offset: 4; indent-tabs-mode: nil; -*- */
 
 const Clutter = imports.gi.Clutter;
 const Mainloop = imports.mainloop;
+const Meta = imports.gi.Meta;
 const Shell = imports.gi.Shell;
+const Tweener = imports.tweener.tweener;
 
 const Main = imports.ui.main;
 
+const SWITCH_ANIMATION_TIME = 0.5;
+
 function WindowManager() {
     this._init();
 }
 
 WindowManager.prototype = {
     _init : function() {
-	let global = Shell.global_get();
-        let shellwm = global.window_manager;
+        let me = this;
 
-	shellwm.connect('switch-workspace',
-	    function(o, from, to, direction) {
-	        let actors = shellwm.get_switch_workspace_actors();
-		for (let i = 0; i < actors.length; i++) {
-		    if (actors[i].get_workspace() == from)
-			actors[i].hide();
-		    else if (actors[i].get_workspace() == to)
-			actors[i].show();
-		}
-	    });
+        this._global = Shell.global_get();
+        this._shellwm = this._global.window_manager;
+
+        this._switchData = null;
+        this._shellwm.connect('switch-workspace',
+            function(o, from, to, direction) {
+                let actors = me._shellwm.get_switch_workspace_actors();
+                me.switchWorkspace(actors, from, to, direction);
+            });
+        this._shellwm.connect('kill-switch-workspace',
+            function(o) {
+                me.switchWorkspaceDone();
+            });
+    },
+    
+    switchWorkspace : function(windows, from, to, direction) {
+        /* @direction is the direction that the "camera" moves, so the
+         * screen contents have to move one screen's worth in the
+         * opposite direction.
+         */
+        let xDest = 0, yDest = 0;
+
+        if (direction == Meta.MotionDirection.UP ||
+            direction == Meta.MotionDirection.UP_LEFT ||
+            direction == Meta.MotionDirection.UP_RIGHT)
+                yDest = this._global.screen_height;
+        else if (direction == Meta.MotionDirection.DOWN ||
+            direction == Meta.MotionDirection.DOWN_LEFT ||
+            direction == Meta.MotionDirection.DOWN_RIGHT)
+                yDest = -this._global.screen_height;
+
+        if (direction == Meta.MotionDirection.LEFT ||
+            direction == Meta.MotionDirection.UP_LEFT ||
+            direction == Meta.MotionDirection.DOWN_LEFT)
+                xDest = this._global.screen_width;
+        else if (direction == Meta.MotionDirection.RIGHT ||
+                 direction == Meta.MotionDirection.UP_RIGHT ||
+                 direction == Meta.MotionDirection.DOWN_RIGHT)
+                xDest = -this._global.screen_width;
+
+        let switchData = {};
+        this._switchData = switchData;
+        switchData.inGroup = new Clutter.Group();
+        switchData.outGroup = new Clutter.Group();
+        switchData.windows = [];
+
+        let wgroup = this._global.window_group;
+        wgroup.add_actor(switchData.inGroup);
+        wgroup.add_actor(switchData.outGroup);
+
+        for (let i = 0; i < windows.length; i++) {
+            let window = windows[i];
+            if (window.get_workspace() == from) {
+                switchData.windows.push({ window: window,
+                                          parent: window.get_parent() });
+                window.reparent(switchData.outGroup);
+            } else if (window.get_workspace() == to) {
+                switchData.windows.push({ window: window,
+                                          parent: window.get_parent() });
+                window.reparent(switchData.inGroup);
+                window.show_all();
+            }
+        }
+
+        switchData.inGroup.set_position(-xDest, -yDest);
+        switchData.inGroup.raise_top();
+
+        Tweener.addTween(switchData.outGroup,
+                         { x: xDest,
+                           y: yDest,
+                           time: SWITCH_ANIMATION_TIME,
+                           transition: "easeOutBack",
+                           onComplete: this.switchWorkspaceDone
+                         });
+        Tweener.addTween(switchData.inGroup,
+                         { x: 0,
+                           y: 0,
+                           time: SWITCH_ANIMATION_TIME,
+                           transition: "easeOutBack"
+                         });
+    },
+    
+    switchWorkspaceDone : function() {
+        let switchData = this._switchData;
+        if (!switchData)
+            return;
+        this._switchData = null;
+
+        for (let i = 0; i < switchData.windows.length; i++) {
+                let w = switchData.windows[i];
+                if (w.window.get_parent() == switchData.outGroup) {
+                    w.window.reparent(w.parent);
+                    w.window.hide();
+                } else
+                    w.window.reparent(w.parent);
+        }
+        Tweener.removeTweens(switchData.inGroup);
+        Tweener.removeTweens(switchData.outGroup);
+        switchData.inGroup.destroy();
+        switchData.outGroup.destroy();
+
+        this._shellwm.completed_switch_workspace();
     }
+
 };
diff --git a/src/shell-wm.c b/src/shell-wm.c
index a7d2b3ca8..34ba3a7c3 100644
--- a/src/shell-wm.c
+++ b/src/shell-wm.c
@@ -7,6 +7,7 @@
 struct _ShellWM {
   GObject parent;
 
+  MutterPlugin *plugin;
   GList *switch_workspace_actors;
 };
 
@@ -104,9 +105,65 @@ shell_wm_switch_workspace (const GList **actors,
   shell_wm_set_switch_workspace_actors (wm, (GList *)*actors);
   g_signal_emit (wm, shell_wm_signals[SWITCH_WORKSPACE], 0,
                  from, to, direction);
+}
+
+/**
+ * shell_wm_get_switch_workspace_actors:
+ * @wm: the #ShellWM
+ *
+ * A workaround for a missing feature in gobject-introspection. Returns
+ * the list of windows involved in a switch-workspace operation (which
+ * cannot be passed directly to the signal handler because there's no
+ * way to annotate the element-type of a signal parameter.)
+ *
+ * Return value: (element-type MutterWindow) (transfer full): the list
+ * of windows
+ **/
+GList *
+shell_wm_get_switch_workspace_actors (ShellWM *wm)
+{
+  GList *l;
+
+  for (l = wm->switch_workspace_actors; l; l = l->next)
+    g_object_ref (l->data);
+  return g_list_copy (wm->switch_workspace_actors);
+}
+
+static void
+shell_wm_set_switch_workspace_actors (ShellWM *wm, GList *actors)
+{
+  const GList *l;
+
+  for (l = wm->switch_workspace_actors; l; l = l->next)
+    g_object_unref (l->data);
+  g_list_free (wm->switch_workspace_actors);
+  wm->switch_workspace_actors = g_list_copy (actors);
+  for (l = wm->switch_workspace_actors; l; l = l->next)
+    g_object_ref (l->data);
+}
+
+/**
+ * shell_wm_completed_switch_workspace:
+ * @wm: the ShellWM
+ *
+ * The plugin must call this when it has finished switching the
+ * workspace.
+ **/
+void
+shell_wm_completed_switch_workspace (ShellWM *wm)
+{
+  g_return_if_fail (wm->switch_workspace_actors != NULL);
+
+  /* mutter_plugin_effect_completed() requires us to pass a window,
+   * though it doesn't matter *which* window in this case.
+   */
+  mutter_plugin_effect_completed (wm->plugin,
+                                  wm->switch_workspace_actors->data,
+                                  MUTTER_PLUGIN_SWITCH_WORKSPACE);
   shell_wm_set_switch_workspace_actors (wm, NULL);
 }
 
+
 static void
 shell_wm_kill_effect (MutterWindow *actor,
                       gulong        events)
@@ -141,6 +198,11 @@ shell_wm_kill_effect (MutterWindow *actor,
 ShellWM *
 shell_wm_new (MutterPlugin *plugin)
 {
+  ShellWM *wm;
+
+  wm = g_object_new (SHELL_TYPE_WM, NULL);
+  wm->plugin = plugin;
+
 #ifdef NOT_YET
   plugin->minimize         = shell_wm_minimize;
   plugin->maximize         = shell_wm_maximize;
@@ -151,44 +213,5 @@ shell_wm_new (MutterPlugin *plugin)
   plugin->switch_workspace = shell_wm_switch_workspace;
   plugin->kill_effect      = shell_wm_kill_effect;
 
-  return g_object_new (SHELL_TYPE_WM, NULL);
-}
-
-/**
- * shell_wm_get_switch_workspace_actors:
- * @wm: the #ShellWM
- *
- * A workaround for a missing feature in gobject-introspection. Returns
- * the list of windows involved in a switch-workspace operation (which
- * cannot be passed directly to the signal handler because there's no
- * way to annotate the element-type of a signal parameter.)
- *
- * You must call this from the #ShellWM::switch-workspace signal
- * handler itself; if you need the value again later, you must save a
- * copy yourself.
- *
- * Return value: (element-type MutterWindow) (transfer full): the list
- * of windows
- **/
-GList *
-shell_wm_get_switch_workspace_actors (ShellWM *wm)
-{
-  GList *l;
-
-  for (l = wm->switch_workspace_actors; l; l = l->next)
-    g_object_ref (l->data);
-  return g_list_copy (wm->switch_workspace_actors);
-}
-
-static void
-shell_wm_set_switch_workspace_actors (ShellWM *wm, GList *actors)
-{
-  const GList *l;
-
-  for (l = wm->switch_workspace_actors; l; l = l->next)
-    g_object_unref (l->data);
-  g_list_free (wm->switch_workspace_actors);
-  wm->switch_workspace_actors = g_list_copy (actors);
-  for (l = wm->switch_workspace_actors; l; l = l->next)
-    g_object_ref (l->data);
+  return wm;
 }
diff --git a/src/shell-wm.h b/src/shell-wm.h
index 54d81a32e..d448239aa 100644
--- a/src/shell-wm.h
+++ b/src/shell-wm.h
@@ -27,6 +27,7 @@ GType    shell_wm_get_type                    (void) G_GNUC_CONST;
 ShellWM *shell_wm_new                         (MutterPlugin *plugin);
 
 GList   *shell_wm_get_switch_workspace_actors (ShellWM      *wm);
+void     shell_wm_completed_switch_workspace  (ShellWM      *wm);
 
 G_END_DECLS