[gnome-shell] overview: Move ::scroll-event signal handling (again)

[Florian Müllner <fmuellner src gnome org>]

commit 99b5e10acf9e84af3d18dad831b4c7488cdc5f0f
Author: Florian Müllner <fmuellner gnome org>
Date:   Sat Jul 2 11:16:22 2016 +0200

    overview: Move ::scroll-event signal handling (again)
    
    Commit c39ffa111 moved the signal handling from the controls- to the
    background-group to enable scrolling on non-primary monitors.
    However this broke scrolling on reactive overview elements as the
    workspace switcher, as they're not descendants of the background.
    To fix, move scroll-event handling to the overview group itself,
    which is the common ancestor of all overview elements.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=768316

 js/ui/layout.js   |    3 ++-
 js/ui/overview.js |    6 +++---
 2 files changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/js/ui/layout.js b/js/ui/layout.js
index 9d481cf..aaf9da5 100644
--- a/js/ui/layout.js
+++ b/js/ui/layout.js
@@ -220,7 +220,8 @@ const LayoutManager = new Lang.Class({
         global.stage.add_child(this.uiGroup);
 
         this.overviewGroup = new St.Widget({ name: 'overviewGroup',
-                                             visible: false });
+                                             visible: false,
+                                             reactive: true });
         this.addChrome(this.overviewGroup);
 
         this.screenShieldGroup = new St.Widget({ name: 'screenShieldGroup',
diff --git a/js/ui/overview.js b/js/ui/overview.js
index ea6b3ec..1af8706 100644
--- a/js/ui/overview.js
+++ b/js/ui/overview.js
@@ -124,9 +124,6 @@ const Overview = new Lang.Class({
         Main.layoutManager.overviewGroup.add_child(this._backgroundGroup);
         this._bgManagers = [];
 
-        this._backgroundGroup.connect('scroll-event',
-                                      Lang.bind(this, this._onScrollEvent));
-
         this._desktopFade = new St.Widget();
         Main.layoutManager.overviewGroup.add_child(this._desktopFade);
 
@@ -155,6 +152,9 @@ const Overview = new Lang.Class({
             dragMotion: Lang.bind(this, this._onDragMotion)
         };
 
+
+        Main.layoutManager.overviewGroup.connect('scroll-event',
+                                                 Lang.bind(this, this._onScrollEvent));
         Main.xdndHandler.connect('drag-begin', Lang.bind(this, this._onDragBegin));
         Main.xdndHandler.connect('drag-end', Lang.bind(this, this._onDragEnd));