title: How to fit button's size in Tkinter?
body: <p>I have been working with <code>python</code> for a week and with <code>Tkinter</code> even less, so sorry if my question will be typical.</p>
  
  <hr>
  
  <p>I want to write a simple GUI for an oscilloscope. And I have encountered a problem with how to fit button's size to size of other buttons. Here is what I have reached to (screenshot). 
  <a href="https://i.stack.imgur.com/3rb9o.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3rb9o.png" alt="enter image description here"></a>
  You might notice that size of <code>trigger</code> and <code>horizontal</code> buttons are less than all <code>channel</code> group. So how to fit their size <em>exactly</em> to <code>channel</code> group size. Here is a piece of my code.</p>
  
  <pre><code>class StartPage(tk.Frame):
  
  def __init__(self, parent, controller):
      tk.Frame.__init__(self, parent)
      self.controller = controller
      startLabel = tk.Label(self,
                            text="Start page")
      startLabel.pack(side="top")
  
      quitGroup = tk.Frame(self)
      quitGroup.pack(side="bottom")
      quitButton = tk.Button(quitGroup, text="Quit",
                             command=quit,
                             bg="pink")
      quitButton.grid(pady=10)
  
      channelGroup = tk.Frame(self)
      channelGroup.pack(side=tk.LEFT)
      chLabel = tk.Label(channelGroup,
                         text="Channel group")
      chLabel.grid(pady=10)
  
      ch1Button = tk.Button(channelGroup, text="CH1 Settings",
                            command=lambda: controller.show_frame("CH1"))
      ch1Button.grid(row=1, column=0)
  
      ch2Button = tk.Button(channelGroup, text="CH2 Settings",
                            command=lambda: controller.show_frame("CH2"))
      ch2Button.grid(row=2, column=0)
  
      ch3Button = tk.Button(channelGroup, text="CH3 Settings",
                            command=lambda: controller.show_frame("CH3"))
  
      ch3Button.grid(row=3, column=0)
  
      ch4Button = tk.Button(channelGroup, text="CH4 Settings",
                            command=lambda: controller.show_frame("CH4"))
      ch4Button.grid(row=4, column=0)
  
      triggerGroup = tk.Frame(self)
      triggerGroup.pack(side=tk.LEFT)
      trigLabel = tk.Label(triggerGroup,
                            text="Trigger group")
      trigLabel.grid(pady=10)
      trigButton = tk.Button(triggerGroup, text="Trigger Settings",
                             command=lambda: controller.show_frame("Trigger"))
      trigButton.grid(row=1, column=0)
      trigButton.grid(ipady=43)#43? What?
  
      horizGroup = tk.Frame(self)
      horizGroup.pack(side=tk.LEFT)
      horizLabel = tk.Label(horizGroup,
                            text="Horizontal group")
      horizLabel.grid(pady=10)
      horizButton = tk.Button(horizGroup,
                              text="Horizontal settings",
                              command=lambda: controller.show_frame("Horizontal"))
      horizButton.grid(row=1, column=0)
      horizButton.grid(ipady=43)#you again ...
  </code></pre>
  
  <p>Is it possible if those buttons are in different frames? I would like leave it so.</p>