Use a custom actor for the uiGroup.

This actor is more efficient and idle updates on the uiGroup
are significantly reduced.

ref:
https://gitlab.gnome.org/GNOME/gnome-shell/-/commit/6b924c00c5c171ce11663c855bad2ec3d230f158

Author: mtwebster

js/ui/layout.js

@@ -6,6 +6,7 @@
  */
 const Clutter = imports.gi.Clutter;
 const Cinnamon = imports.gi.Cinnamon;
+const GObject = imports.gi.GObject;
 const GLib = imports.gi.GLib;
 const Gio = imports.gi.Gio;
 const Lang = imports.lang;
@@ -51,6 +52,19 @@ Monitor.prototype = {
     }
 };
 
+const UiActor = GObject.registerClass(
+class UiActor extends St.Widget {
+    vfunc_get_preferred_width(_forHeight) {
+        let width = global.stage.width;
+        return [width, width];
+    }
+
+    vfunc_get_preferred_height(_forWidth) {
+        let height = global.stage.height;
+        return [height, height];
+    }
+});
+
 /**
  * #LayoutManager
  *
@@ -594,7 +608,6 @@ Chrome.prototype = {
                 visible = false;
             else
                 visible = true;
-            Main.uiGroup.set_skip_paint(actorData.actor, !visible);
         }
         this._queueUpdateRegions();
     },
@@ -733,8 +746,7 @@ Chrome.prototype = {
 
             if (wantsInputRegion
                 && actorData.affectsInputRegion
-                && actorData.actor.get_paint_visibility()
-                && !Main.uiGroup.get_skip_paint(actorData.actor)) {
+                && actorData.actor.get_paint_visibility()) {
 
                 let rect = new Meta.Rectangle({ x: x, y: y, width: w, height: h});
 

js/ui/main.js

@@ -343,27 +343,9 @@ function start() {
     keybindingManager = new Keybindings.KeybindingManager();
     deskletContainer = new DeskletManager.DeskletContainer();
 
-    // Set up stage hierarchy to group all UI actors under one container.
-    uiGroup = new Cinnamon.GenericContainer({ name: 'uiGroup' });
-    // see https://gitlab.gnome.org/GNOME/gnome-shell/-/commit/73d8c82640f6125cfbf80
-    this.uiGroup.set_flags(Clutter.ActorFlags.NO_LAYOUT);
-
-    uiGroup.connect('allocate',
-                    function (actor, box, flags) {
-                        let children = uiGroup.get_children();
-                        for (let i = 0; i < children.length; i++)
-                            children[i].allocate_preferred_size(flags);
-                    });
-    uiGroup.connect('get-preferred-width',
-                    function(actor, forHeight, alloc) {
-                        let width = global.stage.width;
-                        [alloc.min_size, alloc.natural_size] = [width, width];
-                    });
-    uiGroup.connect('get-preferred-height',
-                    function(actor, forWidth, alloc) {
-                        let height = global.stage.height;
-                        [alloc.min_size, alloc.natural_size] = [height, height];
-                    });
+    uiGroup = new Layout.UiActor({ name: 'uiGroup' });
+    uiGroup.set_flags(Clutter.ActorFlags.NO_LAYOUT);
+
     global.background_actor.hide();
     global.reparentActor(global.window_group, uiGroup);
     global.reparentActor(global.overlay_group, uiGroup);