import tkinter as tk
import time

counter = 0
lt = time.localtime()
def counter_label(label_Zeit, label_Datum):
  counter = 0
  def count():
    global counter
    counter += 1
    lt = time.localtime()
    label_Zeit.config(text="{0:02d}:{1:02d}:{2:02d} ".format(lt[3], lt[4], lt[5]))
    label_Datum.config(text="{0:02d}.{1:02d}.{2:4d}".format(lt[2], lt[1], lt[0]))
    label_Dauer.config(text="{0:d}".format(counter))
    label_Zeit.after(1000, count)
  count()

root = tk.Tk()
root.resizable(False, False)
root.wm_attributes("-topmost", 1)
root.title("")
label_Zeit = tk.Label(root, fg="blue2", font=("Realpolitik", 16))
label_Datum = tk.Label(root, fg="dark blue", font=("Ink Free",16, "bold"))
label_Dauer = tk.Label(root, fg="dark blue", font=("Ink Free",16, "bold"))
label_Zeit.pack()
label_Datum.pack()
label_Dauer.pack()
counter_label(label_Zeit, label_Datum)
button = tk.Button(root, text='Stop',fg="DodgerBlue2", font=("Realpolitik Semi-Bold Semi-Ital", 16), width=25, command=root.destroy)
button.pack()
root.mainloop()