title: _tkinter.TclError: can't invoke "label" command: application has been destroyed
body: <p>Hi this is my first post on this website. Recently I was having my programming class and we were learning about tkinter. I tried to run the program the box thing would show up but the text inside the box wouldn't show up. This error showed up "_tkinter.TclError: can't invoke "label" command: application has been destroyed". What is the issue and how can I fix it? Thanks for your help.</p>
  
  <pre><code>    from tkinter import *
  
      #*******************
      def greet():
          n=name.get()
          print(f"{n},good morning")
  
      #create a window(screen)
      screen=Tk()
      screen.title("GUI thing")
      screen.geometry("380x300")
      screen.mainloop()
      myfont="Times 14 bold"
  
      # Create a label and put it on the grid
      Label(screen,text="Enter Name:",font= myfont).grid(row=0,column=0)
  
      # Create an entry box
      name=StringVar()
      Entry(screen,width=15,font=myfont,textvariable=name).grid(row=0,column=1)
  
      # Create a button
      Button(screen,text="Clik moi",font=myfont,bg="green",fg="white",command=greet).grid(row=1,colum=0)`enter code here`
  </code></pre>