WindowList: fix behavior on fullscreen

LayoutManager will take care of our visibility, but we need to
adjust the message tray anchor point manually. Also, we must not
show ourselves when coming out of the overview if we're in fullscreen.

https://bugzilla.gnome.org/show_bug.cgi?id=696929

extensions/window-list/extension.js

@@ -423,12 +423,17 @@ const WindowList = new Lang.Class({
 
         this._overviewHidingId =
             Main.overview.connect('hiding', Lang.bind(this, function() {
-                this.actor.show();
+                this.actor.visible = !Main.layoutManager.primaryMonitor.inFullscreen;
                 this._updateKeyboardAnchor();
                 this._updateMessageTrayAnchor();
             }));
         this._updateMessageTrayAnchor();
 
+        this._fullscreenChangedId =
+            global.screen.connect('in-fullscreen-changed', Lang.bind(this, function() {
+                this._updateMessageTrayAnchor();
+            }));
+
         this._settings = Convenience.getSettings();
         this._groupingModeChangedId =
             this._settings.connect('changed::grouping-mode',
@@ -584,6 +589,8 @@ const WindowList = new Lang.Class({
         Main.overview.disconnect(this._overviewShowingId);
         Main.overview.disconnect(this._overviewHidingId);
 
+        global.screen.disconnect(this._fullscreenChangedId);
+
         this._settings.disconnect(this._groupingModeChangedId);
 
         let windows = Meta.get_window_actors(global.screen);