[gnome-shell] altTab: Fix thumbnail size calculation for some dual-head setups

[Adel Gadllah <agadllah src gnome org>]

commit 00ed2973b2d71f2769ef2966cdf60017522a834e
Author: Marius Gedminas <marius gedmin as>
Date:   Thu Feb 23 20:38:01 2012 +0200

    altTab: Fix thumbnail size calculation for some dual-head setups
    
    The old formula worked only when the primary monitor was positioned at the
    top of the virtual desktop.  When that was not the case, the available
    space was miscalculated sometimes resulting in negative numbers, which in
    the end produced strangely vertically stretched window thumbnails.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=651130

 js/ui/altTab.js |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/js/ui/altTab.js b/js/ui/altTab.js
index 85d4792..25e6db7 100644
--- a/js/ui/altTab.js
+++ b/js/ui/altTab.js
@@ -125,7 +125,7 @@ const AltTabPopup = new Lang.Class({
             if (childBox.x2 > primary.x + primary.width - rightPadding)
                 childBox.x2 = primary.x + primary.width - rightPadding;
             childBox.y1 = this._appSwitcher.actor.allocation.y2 + spacing;
-            this._thumbnails.addClones(primary.height - bottomPadding - childBox.y1);
+            this._thumbnails.addClones(primary.y + primary.height - bottomPadding - childBox.y1);
             let [childMinHeight, childNaturalHeight] = this._thumbnails.actor.get_preferred_height(-1);
             childBox.y2 = childBox.y1 + childNaturalHeight;
             this._thumbnails.actor.allocate(childBox, flags);