diff --git a/waypoint_manager/scripts/manager_GUI.py b/waypoint_manager/scripts/manager_GUI.py
index 2e25141..802bca5 100755
--- a/waypoint_manager/scripts/manager_GUI.py
+++ b/waypoint_manager/scripts/manager_GUI.py
@@ -2,6 +2,7 @@
 import tkinter.filedialog
 import math
 import ruamel.yaml
+import gc
 from pathlib import Path
 from tkinter import messagebox
 from lib.mymaplib import MyMap
@@ -132,6 +133,7 @@
             messagebox.showerror(title="Format error", message="Selected map file is unexpected format.")
             return
         try:
+            del self.mymap
             self.mymap = MyMap(Path(map_path), map_yaml)
         except FileNotFoundError:
             messagebox.showerror(title="Image file is not found", message="\""+map_yaml["image"]+"\"  is not found.")
@@ -166,6 +168,7 @@
             self.menu_open_waypoints()
         else:
             self.plot_waypoints()
+        gc.collect()
         return
     
 
@@ -176,12 +179,15 @@
         if (self.waypoints is not None) and (self.master.title()[0] == "*"):
             yn = messagebox.askyesno("Confirm", "Do you want to save changes to " + str(self.waypoints_filepath))
             if yn: self.save_waypoints(str(self.waypoints_filepath)) # Yes
-            self.canvas.delete("all")
-            self.draw_image()
-            self.plot_origin()
+            self.master.title(str(self.master.title()).replace("* " + self.waypoints_filepath.name + " - ", ""))
+        elif (self.waypoints is not None):
             self.master.title(str(self.master.title()).replace(self.waypoints_filepath.name + " - ", ""))
-            if (self.wp_info_win is not None) and (self.wp_info_win.winfo_exists()):
-                self.wp_info_win.destroy()
+
+        self.canvas.delete("all")
+        self.draw_image()
+        self.plot_origin()
+        if (self.wp_info_win is not None) and (self.wp_info_win.winfo_exists()):
+            self.wp_info_win.destroy()
 
         filepath = tkinter.filedialog.askopenfilename(
             parent=self.master,
@@ -195,6 +201,7 @@
         if (not "waypoints" in wp_yaml.keys()) or (not "finish_pose" in wp_yaml.keys()):
             messagebox.showerror(title="Format error", message="Selected waypoints file is unexpected format.")
             return
+        del self.waypoints
         self.waypoints = WaypointList(wp_yaml)
         self.finish_pose = FinishPose(wp_yaml)
         self.waypoints_filepath = Path(filepath)
@@ -204,6 +211,7 @@
         self.file_menu.entryconfigure("Save", state=tk.NORMAL)
         self.file_menu.entryconfigure("Save As", state=tk.NORMAL)
         self.popup_menu.entryconfigure("Add waypoint here", state=tk.NORMAL)
+        gc.collect()
         return
     
 
@@ -627,6 +635,7 @@
             self.wp_info_win.destroy()
             self.disp_waypoint_info(self.editing_waypoint_id)
             self.update_title()
+            gc.collect()
             return
         add_btn = tk.Button(sub_win, text="Add", width=5, height=1, font=font, anchor=tk.CENTER, bg="#AFA")
         add_btn["command"] = add_param
@@ -664,6 +673,7 @@
         self.editing_waypoint_id = None
         self.moving_waypoint = False
         self.wp_info_win.destroy()
+        gc.collect()
         return