我有一個(gè)可滾動(dòng)框架，鼠標(biāo)滾輪綁定到滾動(dòng)，但是當(dāng)框架小于畫布時(shí)，我可以在其上方滾動(dòng) - 如何將框架保持在畫布頂部？這是代碼的最小版本：import tkinter as tkclass Gui:    def __init__(self, master):        self.root = master        self.canvas = tk.Canvas(self.root)        self.frame = tk.Frame(self.canvas,bg='white')        self.scroll = tk.Scrollbar(self.canvas,orient='vertical', command=self.canvas.yview)        self.canvas.configure(yscrollcommand=self.scroll.set)        self.scroll.pack(side='right', fill='y')        self.canvas.place(relheight=1, relwidth=0.85, relx=0.15)        self.canvas_frame = self.canvas.create_window((0,0), window=self.frame, anchor='nw')        self.frame.bind('<Configure>', self.onFrameConfigure)        self.canvas.bind_all('<MouseWheel>', lambda event: self.canvas.yview_scroll(int(-1*(event.delta/120)), 'units'))        self.addToFrame()    def onFrameConfigure(self, event):        self.canvas.configure(scrollregion=self.canvas.bbox('all'))    def addToFrame(self):        self.label = tk.Label(self.frame,text='Label')        self.label.pack()        if __name__ == "__main__":    root = tk.Tk()    gui = Gui(root)    root.mainloop()