Tkinter Tabcontrol的Example 2标签页无法显示ComboNew组合框

Example 2标签页空白核心是两个编写错误，和滚动条框架设计无关：

• 滚动条父组件传参错误：创建Example 2页的垂直滚动条时，父容器填成了第一个Example标签的Framea，不是Example 2自身的容器b，滚动条根本没有挂载到当前标签页下
• 缺失布局逻辑：Example 2页创建完canvas、scrollbar控件后，没有调用pack()方法做布局渲染，控件仅在内存中创建、没有添加到页面视图，因此打开后全空白
• 额外优化：原滚动实现未做宽度自适应、鼠标滚轮支持，修正版补充了这两个常用能力，缩放窗口不会错位，也可以直接用滚轮滚动长内容。

from tkinter import ttk
import tkinter as tk

window = tk.Tk()  
window.attributes('-zoomed', True)
window.configure(bg='#f3f2f2')

style = ttk.Style(window)
style.theme_use('clam')

#######################
tabControl = ttk.Notebook(window, style='Custom.TNotebook', width=700, height=320)

cronaca = ttk.Notebook(tabControl)
politica = ttk.Notebook(tabControl)
gossip = ttk.Notebook(tabControl)

tabControl.add(cronaca, text ='Cronaca')
tabControl.add(politica, text ='Politica')
tabControl.add(gossip, text ='Gossip')
tabControl.pack(fill='both', expand=True, padx=1, pady=1) # 替换原place布局，适配窗口缩放

#CRONACA 分类页
incident = ttk.Notebook(cronaca)
cronaca.add(incident, text="Incidente")

# 通用滚动适配函数
def config_scroll_area(scroll_container):
    # 传入页容器，返回可放置内容的滚动帧
    canvas = tk.Canvas(scroll_container, highlightthickness=0, bg='#f3f2f2')
    scrollbar = ttk.Scrollbar(scroll_container, orient="vertical", command=canvas.yview)
    scroll_frame = ttk.Frame(canvas)

    # 绑定滚动区域
    scroll_frame.bind(
        "<Configure>",
        lambda e: canvas.configure(scrollregion=canvas.bbox("all"))
    )
    # 绑定宽度自适应
    canvas_item = canvas.create_window((0, 0), window=scroll_frame, anchor="nw")
    canvas.bind("<Configure>", lambda e: canvas.itemconfig(canvas_item, width=e.width))
    canvas.configure(yscrollcommand=scrollbar.set)

    # 布局
    canvas.pack(side="left", fill="both", expand=True)
    scrollbar.pack(side="right", fill="y")

    # 鼠标滚轮绑定（进入页面生效，离开解绑避免冲突）
    def _on_mousewheel(event):
        canvas.yview_scroll(int(-1*(event.delta/120)), "units")
    def _bind_wheel(e):
        canvas.bind_all("<MouseWheel>", _on_mousewheel)
    def _unbind_wheel(e):
        canvas.unbind_all("<MouseWheel>")
    scroll_container.bind("<Enter>", _bind_wheel)
    scroll_container.bind("<Leave>", _unbind_wheel)

    return scroll_frame

# Example 标签页
a = ttk.Frame(incident)
incident.add(a, text="Example")
scroll_frame1 = config_scroll_area(a)

combo1=ttk.Combobox(scroll_frame1, width = 18)
combo1.place(x=20, y=20)
combo1['value'] = ["text1", "text2"]

combo2=ttk.Combobox(scroll_frame1, width = 18)
combo2.place(x=20, y=80)
combo2['value'] = ["text1", "text2"]

combo3=ttk.Combobox(scroll_frame1, width = 18)
combo3.place(x=20, y=140)
combo3['value'] = ["text1", "text2"]

combo4=ttk.Combobox(scroll_frame1, width = 18)
combo4.place(x=20, y=200)
combo4['value'] = ["text1", "text2"]

# Example 2 标签页
b = ttk.Frame(incident)
incident.add(b, text="Example 2")
scroll_frame2 = config_scroll_area(b)

comboNew=ttk.Combobox(scroll_frame2, width = 18)
comboNew.place(x=20, y=20)
comboNew['value'] = ["text1", "text2"]

window.mainloop()

内容的提问来源于stack exchange，提问作者user18313765