[gnome-shell/wip/fmuellner/window-preview-translucency: 171/171] workspace: Set offscreen redirect on window previews

[Florian Müllner <fmuellner src gnome org>]

commit 8da66c59952d9a7eb01818a9ff6eb7e2fec3a422
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 868f91bc9..4c2cbf064 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;
     }