Use add_child in all the possible places

add_child() method does work in Gnome 45 too for nearly all the
places. There is only one place where it produces a problem,
which is with the scrollView element. Using add_actor() there
is mandatory to keep compatibility with Gnome 45, at least
until we discover why it breaks the size detection.

I suspect that when this problem is fixed in Gnome 45, it will
also fix the size and placement problems in Gnome 46.

appIcons.js

@@ -997,7 +997,7 @@ const DockAppIconMenu = class DockAppIconMenu extends PopupMenu.PopupMenu {
         });
         source.connect('destroy', () => this.destroy());
 
-        Utils.addActor(Main.uiGroup, this.actor);
+        Main.uiGroup.add_child(this.actor);
 
         const {remoteModel} = Docking.DockManager.getDefault();
         const remoteModelApp = remoteModel?.lookupById(this._source?.app?.id);

dash.js

@@ -168,9 +168,9 @@ export const DockDash = GObject.registerClass({
             x_expand: this._isHorizontal,
         });
         this._box._delegate = this;
-        Utils.addActor(this._dashContainer, this._scrollView);
-        Utils.addActor(this._boxContainer, this._box);
+        this._boxContainer.add_child(this._box);
         Utils.addActor(this._scrollView, this._boxContainer);
+        this._dashContainer.add_child(this._scrollView);
 
         this._showAppsIcon = new AppIcons.DockShowAppsIcon(this._position);
         this._showAppsIcon.show(false);

docking.js

@@ -404,7 +404,7 @@ const DockedDash = GObject.registerClass({
         // Add dash container actor and the container to the Chrome.
         this.set_child(this._slider);
         this._slider.set_child(this._box);
-        Utils.addActor(this._box, this.dash);
+        this._box.add_child(this.dash);
 
         // Add aligning container without tracking it for input region
         this._trackDock();

windowPreview.js

@@ -60,7 +60,7 @@ export class WindowPreviewMenu extends PopupMenu.PopupMenu {
         });
         this._destroyId = this._source.connect('destroy', this.destroy.bind(this));
 
-        Utils.addActor(Main.uiGroup, this.actor);
+        Main.uiGroup.add_child(this.actor);
 
         this.connect('destroy', this._onDestroy.bind(this));
     }
@@ -109,7 +109,7 @@ class WindowPreviewList extends PopupMenu.PopupMenuSection {
         this.isHorizontal = position === St.Side.BOTTOM || position === St.Side.TOP;
         this.box.set_vertical(!this.isHorizontal);
         this.box.set_name('dashtodockWindowList');
-        Utils.addActor(this.actor, this.box);
+        this.actor.add_child(this.box);
         this.actor._delegate = this;
 
         this._shownInitially = false;
@@ -359,16 +359,16 @@ class WindowPreviewMenuItem extends PopupMenu.PopupBaseMenuItem {
                 ? Clutter.ActorAlign.START : Clutter.ActorAlign.END,
             y_align: Clutter.ActorAlign.START,
         });
-        Utils.addActor(this.closeButton, new St.Icon({icon_name: 'window-close-symbolic'}));
+        this.closeButton.add_child(new St.Icon({icon_name: 'window-close-symbolic'}));
         this.closeButton.connect('clicked', () => this._closeWindow());
 
         const overlayGroup = new Clutter.Actor({
             layout_manager: new Clutter.BinLayout(),
             y_expand: true,
         });
 
-        Utils.addActor(overlayGroup, this._cloneBin);
-        Utils.addActor(overlayGroup, this.closeButton);
+        overlayGroup.add_child(this._cloneBin);
+        overlayGroup.add_child(this.closeButton);
 
         const label = new St.Label({text: window.get_title()});
         label.set_style(`max-width: ${PREVIEW_MAX_WIDTH}px`);
@@ -394,7 +394,7 @@ class WindowPreviewMenuItem extends PopupMenu.PopupBaseMenuItem {
             box.add_child(labelBin);
         }
         this._box = box;
-        Utils.addActor(this, box);
+        this.add_child(box);
 
         this._cloneTexture(window);