I have a python code using the Tkinter module, the problem is that I added a validation to an entry and the callback is only executed once, even though it should be executed every time a key event occurs:
#Callback
def isNumber():
print("Callback")
root=tk.Tk()
#Entry con la validacion
entry1=tk.Entry(root, width=30, validate="key", validatecommand=(isNumber))
entry1.pack(pady=20)
#Entry normal sin validación, solo para probar eventos de Foco
entry2=tk.Entry(root, width=10)
entry2.pack()
root.mainloop()