from tkinter import *
root = Tk()
root.title("Aimtocode")
scrollbar = Scrollbar(root)
#scrollbar.pack(side=RIGHT, fill=Y) # Now it's active, but not visible
listbox = Listbox(root)
listbox.pack()
for i in range(100):
listbox.insert(END, i)
# attach listbox to scrollbar
listbox.config(yscrollcommand=scrollbar.set)
listbox2 = Listbox(root)
listbox2.pack(side="right")
for i in range(100):
listbox2.insert(END, i+100)
listbox2.config(yscrollcommand=scrollbar.set)
scrollbar.config(command=listbox.yview)
root.mainloop()