Added the ability to gracefully close the window

window/ChatWindow.java

@@ -113,6 +113,15 @@ public class ChatWindow extends Application {
     @Override
     public void start(Stage primaryStage) {
         stage = primaryStage;
+        stage.setOnCloseRequest(windowEvent -> {
+            try {
+                protoOut.sendPart(username);
+                socket.close();
+                loginWindow.show();
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        });
 
         AnchorPane root = new AnchorPane();
         primaryStage.setMaximized(true);
@@ -216,13 +225,6 @@ public class ChatWindow extends Application {
         }
     }
 
-    @Override
-    public void stop() throws IOException {
-        protoOut.sendPart(username);
-        socket.close();
-        loginWindow.show();
-    }
-
     public ArrayList<String> userList;
 
     private String servername;