[gnome-shell/wip/fmuellner/window-preview-translucency] workspace: Set offscreen redirect on window previews

[Florian Müllner <fmuellner src gnome org>]

commit 07d60a82d1c6caefe733ad67089c6cf6e98c7c42
Author: Florian Müllner <fmuellner gnome org>
Date:   Tue Nov 13 17:24:37 2018 +0100

    workspace: Set offscreen redirect on window previews
    
    Window previews are sometimes shown translucent, for example during
    drags or animations. They can also have attached dialogs, in which
    case the opacity should affect the combination of all windows instead
    of being applied to each window individually, blended together.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/issues/774

 js/ui/workspace.js | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/js/ui/workspace.js b/js/ui/workspace.js
index 5aa9ba66c..8d62be21c 100644
--- a/js/ui/workspace.js
+++ b/js/ui/workspace.js
@@ -127,6 +127,7 @@ var WindowClone = new Lang.Class({
                                      can_focus: true,
                                      accessible_role: Atk.Role.PUSH_BUTTON,
                                      layout_manager: new WindowCloneLayout() });
+        this.actor.set_offscreen_redirect (Clutter.OffscreenRedirect.ALWAYS);
 
         this.actor.add_child(this._windowClone);