[gnome-shell/wip/fmuellner/window-preview-translucency: 476/476] workspace: Set offscreen redirect on window previews

[Florian Müllner <fmuellner src gnome org>]

commit 3fafe3571f41549ff56839e1aa7245fb5655e4db
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, so
    make sure they are redirected as a whole when necessary.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/issues/774

 js/ui/workspace.js | 6 ++++++
 1 file changed, 6 insertions(+)
---
diff --git a/js/ui/workspace.js b/js/ui/workspace.js
index f350763df..924bc57cb 100644
--- a/js/ui/workspace.js
+++ b/js/ui/workspace.js
@@ -130,6 +130,8 @@ var WindowClone = GObject.registerClass({
             layout_manager: new WindowCloneLayout()
         });
 
+        this.set_offscreen_redirect(Clutter.OffscreenRedirect.AUTOMATIC_FOR_OPACITY);
+
         this.add_child(this._windowClone);
 
         this._delegate = this;
@@ -184,6 +186,10 @@ var WindowClone = GObject.registerClass({
         this._closeRequested = false;
     }
 
+    vfunc_has_overlaps() {
+        return this.hasAttachedDialogs();
+    }
+
     set slot(slot) {
         this._slot = slot;
     }