[gnome-shell] dash: Make the show apps button insensitive when we're dragging a non-favorite

[Jasper St. Pierre <jstpierre src gnome org>]

commit 52871c781acb26696adf177e6ab80f138976ca41
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Tue Oct 2 20:53:07 2012 -0300

    dash: Make the show apps button insensitive when we're dragging a non-favorite
    
    This doesn't handle the tooltip case, unfortunately. That will come in a bit.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=685313

 js/ui/dash.js |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)
---
diff --git a/js/ui/dash.js b/js/ui/dash.js
index 047588d..3a7828c 100644
--- a/js/ui/dash.js
+++ b/js/ui/dash.js
@@ -285,8 +285,16 @@ const ShowAppsIcon = new Lang.Class({
             this.setLabelText(_("Show Applications"));
     },
 
-    // Rely on the dragged item being a favorite
     handleDragOver: function(source, actor, x, y, time) {
+        let app = getAppFromSource(source);
+        if (app == null)
+            return DND.DragMotionResult.NO_DROP;
+
+        let id = app.get_id();
+        let isFavorite = AppFavorites.getAppFavorites().isFavorite(id);
+        if (!isFavorite)
+            return DND.DragMotionResult.NO_DROP;
+
         return DND.DragMotionResult.MOVE_DROP;
     },