Adjust unit test to adhere to new menu dropdowns

nion/swift/test/DisplayPanel_test.py

@@ -1398,7 +1398,7 @@ def test_browser_display_panel_produces_context_menu_with_correct_item_count_ove
         self.display_panel.root_container.refresh_layout_immediate()
         self.display_panel.root_container.canvas_widget.on_context_menu_event(40, 40, 40, 40)
         # show, sep, delete, sep, split h, split v, sep, none, sep, data, thumbnails, browser, sep
-        self.assertEqual(20, len(self.document_controller.ui.popup.items))
+        self.assertEqual(19, len(self.document_controller.ui.popup.items))
 
     def test_browser_display_panel_produces_context_menu_with_correct_item_count_over_area_to_right_of_data_item(self):
         d = {"type": "image", "display-panel-type": "browser-display-panel"}