fixed view mode button not working

data/ui/headerbar.glade

@@ -148,7 +148,7 @@
       </packing>
     </child>
     <child>
-      <object class="GtkButton" id="view_mode_menu_btn">
+      <object class="GtkMenuButton" id="view_mode_menu_btn">
         <property name="visible">True</property>
         <property name="sensitive">False</property>
         <property name="can-focus">True</property>

gfeeds/view_mode_menu.py

@@ -6,6 +6,8 @@ class GFeedsViewModeMenu(Gtk.PopoverMenu):
         super().__init__(**kwargs)
         self.set_modal(True)
         self.set_relative_to(relative_to)
+        relative_to.set_popover(self)
+        relative_to.set_sensitive(False)
         self.builder = Gtk.Builder.new_from_resource(
             '/org/gabmus/gfeeds/ui/extra_popover_menu.glade'
         )