# tk_power_listbox.py

# tk_power_listbox.py

from tkinter import *
from random import shuffle
root = Tk()

root.title("tk_power_listbox")

menu_options = list(range(300))

frame = Frame(root)
frame.pack()

entry = Entry(frame)
entry.pack(side=LEFT)

button = Button(frame, text="Click Me")
button.pack(side=LEFT)

label = Label(frame, text="Hello Tkinter")
label.pack(side=LEFT)

listbox = Listbox(frame, height=1, bg='yellow')
for option in menu_options:
    listbox.insert(END, option)
    listbox.pack(side=LEFT)

listbox.activate(10)
listbox.selection_set(10)
selection = listbox.curselection()[0]

def on_active(event):
    global selected_index
    listbox2.itemconfig(selected_index, bg='white')
    selected_index = listbox2.nearest(event.y)
    listbox2.itemconfig(selected_index, bg='yellow')

def on_select(event):
    global selection
    try:
        selection = listbox2.curselection()[0]
        listbox2.activate(selection)
        listbox2.selection_set(selection)
    except: 0

srceen_h = 564 # root.winfo_screenheight():
def on_enter(event):
    global root2, listbox2, selected_index
    try:
        root2.destroy()
    except: 0
    selected_index = 0
    root2 = Toplevel()
    root2.overrideredirect(True)
    Lmenu = min(40, len(menu_options))
    Lb2 = Lmenu * 14
    listbox2 = Listbox(root2, height=Lmenu)
    yyy = root.winfo_y() + 20
    if yyy + Lb2 > srceen_h:
        yyy = srceen_h - Lb2
    root2.geometry("+{}+{}".format(listbox.winfo_x()+root.winfo_x()+8, yyy))
    for option in menu_options:
        listbox2.insert(END, option)

    listbox2.activate(selection)
    listbox2.selection_set(selection)

    scrollbar = Scrollbar(root2, orient=VERTICAL, command=listbox2.yview)
    scrollbar.pack(side=RIGHT, fill=Y)
    scrollbar.config(width=40)
    listbox2.config(yscrollcommand=scrollbar.set)

    root2.bind("<Motion>", on_active)
    root2.bind("<Leave>", on_leave)
    listbox2.bind("<<ListboxSelect>>", on_select)
    listbox2.pack()

def on_leave(event):
    global root2
    x = root.winfo_pointerx()
    geom = root2.geometry()
    w = int(geom.split("x")[0])
    x2 = int(geom.split("+")[1])
    if x > x2 + w - 50 and x < x2 + w:
        return
    listbox.activate(selection)
    listbox.selection_set(selection)
    root2.destroy()

listbox.bind("<Enter>", on_enter)

checkbox = Checkbutton(frame, text="Check Me")
checkbox.pack(side=LEFT)

root.mainloop()