MainWindow: Connect menu close model.

src/View/MainWindow.py

@@ -180,6 +180,7 @@ class ApplicationWindow(QMainWindow, ListedSubWindow, WindowToolKit):
             "action_menu_run_solver": self.run_solver,
             "action_menu_sediment_layers": self.open_sediment_layers,
             "action_menu_edit_reach_sediment_layers": self.open_reach_sediment_layers,
+            "action_menu_close": self.close_model,
             ## Help
             "action_menu_about": self.open_about,
             # ToolBar action