🪲 Fix GTK3

prefs.js

@@ -77,7 +77,7 @@ var PreferencesDialog = class PreferencesDialog {
 
     // Add a menu to the title bar of the preferences dialog.
     this._widget.connect('realize', (widget) => {
-      const window = widget.get_root();
+      const window = utils.gtk4() ? widget.get_root() : widget.get_toplevel();
 
       // Show the version number in the title bar.
       window.set_title(`Burn-My-Windows ${Me.metadata.version}`);

resources/ui/gtk3.ui

@@ -47,7 +47,14 @@
 
   <object class="GtkMenuButton" id="menu-button">
     <property name="menu-model">main-menu</property>
-    <property name="icon-name">open-menu-symbolic</property>
+    <property name="visible">1</property>
+    <child>
+      <object class="GtkImage">
+        <property name="icon-name">open-menu-symbolic</property>
+        <property name="visible">1</property>
+        <property name="icon-size">1</property>
+      </object>
+    </child>
   </object>
 
   <object class="GtkAdjustment" id="destroy-animation-time">