Python 为什么我的标题文本在靠近标题移动按钮时消失？

我为我的程序创建了一个开始按钮来开始刽子手游戏。因此，我还想在“开始”按钮的顶部添加一个标题。但是，当标题离按钮太近时，按钮会消失，如下所示：

from tkinter import *
root = Tk()

root.wm_title("HangMan")

canvas = Canvas(root, height=400, width=800)
canvas.pack()

title = canvas.create_text(400, 100, font=("Times New Roman", 20))
canvas.itemconfig(title, text="WELCOME")


#Creates the pole
def startgame():
    b1.destroy()
    a = canvas.create_rectangle(550,50,550,350,fill = "black")
    b = canvas.create_rectangle(350,50,550,50,fill = "black")
    c = canvas.create_rectangle(350,50,350,90,fill = "black")

b1 = Button(canvas, text="Start Game", width=30, height=20, command=startgame)
canvas.create_window(400, 200, window = b1)

def callback():
    result = e1.get()
    text2 = canvas.create_text(600, 20, anchor = "nw")
    canvas.itemconfig(text2, text = "Player Name: " + result)

e1 = Entry(canvas)
b2 = Button(canvas, text="Enter", width=10,command=callback)


canvas.create_window(250, 350, window = e1)
canvas.create_window(400, 350, window = b2)


e1.delete(0,END)
e1.insert(0, "Enter your name")

#Creates man
#d = canvas.create_oval(325, 90, 375, 140, outline = "black") #head
#e = canvas.create_line(350, 140, 350, 230, fill = "black") #neck and torso
#f = canvas.create_line(300, 125, 350, 175, fill = "black") #left arm
#g = canvas.create_line(400, 125, 350, 175, fill = "black") #right arm
#h = canvas.create_line(350, 230, 310, 300, fill = "black") #left leg
#i = canvas.create_line(350, 230, 390, 300, fill = "black") #right leg


root.mainloop()

---

没关系，我可以通过去掉启动按钮的高度来解决这个问题。很高兴我能解决这个问题：D

b2 = Button(canvas, text="Enter", width=10,command=callback)