--- src/wingpanel/src/PanelWindow.vala	2017-05-14 21:30:04.493149180 +0900
+++ src/wingpanel/src/PanelWindow.vala.new	2017-05-14 21:34:12.288040769 +0900
@@ -65,7 +65,9 @@
         panel = new Widgets.Panel (popover_manager);
         panel.realize.connect (on_realize);
 
+        panel.connect ("enter_notify_event", on_realize);
+        panel.connect ("leave_notify_event", on_idle);
         this.add (panel);
 
         this.set_size_request (monitor_width, -1);
         this.resize (monitor_width, 1);
@@ -83,12 +84,32 @@
         return true;
     }
 
+    private bool animation_unstep () {
+        if (panel_displacement == -1) {
+            return false;
+        }
+
+        panel_displacement++;
+
+        update_panel_dimensions ();
+
+        return true;
+    }
+
     private void on_realize () {
         update_panel_dimensions ();
 
         //Services.BackgroundManager.get_default ().initialize (this.monitor_number, panel_height);
 
-        Timeout.add (300 / panel_height, animation_step);
+        Timeout.add (250 / panel_height, animation_step);
+    }
+
+    private void on_idle () {
+        update_panel_dimensions ();
+
+        //Services.BackgroundManager.get_default ().initialize (this.monitor_number, panel_height);
+
+        Timeout.add (250 / panel_height, animation_unstep);
     }
 
     private void update_panel_dimensions () {