gi.Adw is always defined in fillPreferencesWindow

panelManager.js

@@ -336,8 +336,9 @@ var PanelManager = class {
                 this.bind_property('opacity', view, 'opacity', GObject.BindingFlags.SYNC_CREATE);
                 this.add_child(view);
             } else {
-                // todo exorcise this after the GS 42 release
-                view = new ProxySecondaryMonitorDisplay(i,
+                // No idea why atm, but we need the import at the top of this file and to use the
+                // full imports ns here, otherwise SecondaryMonitorDisplay can't be used ¯\_(ツ)_/¯
+                view = new imports.ui.workspacesView.SecondaryMonitorDisplay(i,
                     this._controls,
                     this._scrollAdjustment,
                     this._fitModeAdjustment,
@@ -504,15 +505,6 @@ var PanelManager = class {
 
 };
 
-// No idea why atm, but we need the import at the top of this file and this
-// "proxy" class, otherwise SecondaryMonitorDisplay can't be used ¯\_(ツ)_/¯
-var ProxySecondaryMonitorDisplay = GObject.registerClass({
-}, class ProxySecondaryMonitorDisplay extends imports.ui.workspacesView.SecondaryMonitorDisplay {
-    _init(...params) {
-        super._init(...params)
-    }
-});
-
 // This class drives long-running icon animations, to keep them running in sync
 // with each other.
 var IconAnimator = class {

prefs.js

@@ -2464,15 +2464,13 @@ function fillPreferencesWindow(window) {
     let preferences = new Preferences();
     let box = new Gtk.Box({orientation: Gtk.Orientation.VERTICAL});
 
-    if (imports.gi.Adw) {
-        // dummy page to prevent 'Extension did not provide any UI'
-        // error until we migrate to Adw
-        let dummyPage = new imports.gi.Adw.PreferencesPage()
-
-        box.append(new imports.gi.Adw.HeaderBar);
-        window.add(dummyPage);
-        window.visible_page = dummyPage
-    }
+    // dummy page to prevent 'Extension did not provide any UI'
+    // error until we migrate to Adw
+    let dummyPage = new imports.gi.Adw.PreferencesPage()
+
+    box.append(new imports.gi.Adw.HeaderBar);
+    window.add(dummyPage);
+    window.visible_page = dummyPage
 
     box.append(preferences.notebook);
     window.set_content(box);