ttk组合框列表值在alt-Tab键切换后保持打开状态

import tkinter as tk
from tkinter import ttk

def on_focus_out(event):
    if event.widget == combobox:
        combobox['state'] = 'readonly'

root = tk.Tk()

combobox = ttk.Combobox(root, values=["Option 1", "Option 2", "Option 3"])
combobox.pack()

combobox.bind('<FocusOut>', on_focus_out)

root.mainloop()

import tkinter as tk
from tkinter import ttk

def on_closing():
    combobox['state'] = 'readonly'
    root.destroy()

root = tk.Tk()

combobox = ttk.Combobox(root, values=["Option 1", "Option 2", "Option 3"])
combobox.pack()

root.protocol("WM_DELETE_WINDOW", on_closing)

root.mainloop()

import tkinter as tk
from tkinter import ttk

def check_combobox_state():
    if combobox['state'] != 'readonly':
        combobox['state'] = 'readonly'
    root.after(100, check_combobox_state)

root = tk.Tk()

combobox = ttk.Combobox(root, values=["Option 1", "Option 2", "Option 3"])
combobox.pack()

root.after(100, check_combobox_state)

root.mainloop()