[gnome-shell] workspace: Hide preview overlays from picks

[Florian Müllner <fmuellner src gnome org>]

commit d15b46f5cb9928ec784f38ef3e4b50d0970ede2b
Author: Florian Müllner <fmuellner gnome org>
Date:   Wed Mar 15 00:36:26 2017 +0100

    workspace: Hide preview overlays from picks
    
    Dragging and dropping app icons is expected to work anywhere over a
    workspace, however overlaid elements are added to a separate hierarchy
    and can thus block valid drop targets. This wasn't much of an issue
    while we had just the window title, but since the addition of the
    focus border, drops on window previews stopped working entirely.
    
    Fix this by hiding all non-reactive overlay elements from picks.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=737166

 js/ui/workspace.js |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/js/ui/workspace.js b/js/ui/workspace.js
index a1d1582..11a65d6 100644
--- a/js/ui/workspace.js
+++ b/js/ui/workspace.js
@@ -471,6 +471,10 @@ const WindowOverlay = new Lang.Class({
         this.title = title;
         this.closeButton = button;
 
+        // Don't block drop targets
+        Shell.util_set_hidden_from_pick(this.title, true);
+        Shell.util_set_hidden_from_pick(this.border, true);
+
         parentActor.add_actor(this.title);
         parentActor.add_actor(this.border);
         parentActor.add_actor(this.closeButton);