title: I want to create a Scrollbar by creating a frame in a canvas widget, but the bar don't show up
body: <p>According to some answers in Stack Overflow, I create a scrollbar by creating a canvas and embed frame into the canvas, but after I do that, I can only click <em>arrow</em> in scrollbar to scroll the window, but the bar don't show up, whatever I shrink the window or create many widgets in frame.</p>
  
  <pre><code>class Basic_frame:
      def __init__(self):
          root.unbind('&lt;Configure&gt;')
          self.frame_canvas = Canvas(
              root, width=i_window_width, height=i_window_height, bg='red')
          self.window_frame = Frame(
              self.frame_canvas)
          self.xscrollbar = Scrollbar(
              self.frame_canvas, orient='horizontal', command=self.frame_canvas.xview)
          self.yscrollbar = Scrollbar(
              self.frame_canvas, orient='vertical', command=self.frame_canvas.yview)
          self.frame_canvas.configure(yscrollcommand=self.yscrollbar.set)
          self.frame_canvas.configure(xscrollcommand=self.xscrollbar.set)
  
          self.frame_canvas.xview_moveto(0)
          self.frame_canvas.yview_moveto(0)
          self.yscrollbar.pack(side='right', fill='y')
          self.xscrollbar.pack(side='bottom', fill='x')
          self.frame_canvas.create_window(
              (0, 0), window=self.window_frame, anchor='nw')
          # self.window_frame.bind('&lt;Configure&gt;', self.scroll_function)
          self.frame_canvas.pack(side=LEFT, fill=BOTH, expand=TRUE)
          self.frame_canvas.bind('&lt;Configure&gt;', self.resize)
          self.window_frame.bind('&lt;Configure&gt;', self.frame_size)
      def frame_size(self, event):
              size = (root.winfo_reqwidth(), root.winfo_reqheight())
              self.frame_canvas.config(scrollregion=(0, 0, 100, 100))
              # self.frame_canvas.configure(scrollregion=self.window_frame.bbox('all'))
              self.frame_canvas.config(width=event.width, height=event.height)
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/0muCM.png" alt="enter image description here">
  <img src="https://i.stack.imgur.com/RF2fM.png" alt="enter image description here"></p>