About the app in background

[Ramvilas RV]

I was trying to make a simple notepad using tkinter and i have used overrideredirect(1) to remove the maximize and other default buttons at the top. I did make a notepad. When i launch the app, it works but the issue is, when i shift to any other app, the notepad app vanishes. while it still shows on the task manager. 

Please tell me why this happens and if there is any way i can avoid it. Thank you in advance..