title: error in using optionmenu widget in tkinter
body: <p>I have written a code in python 2.7 which implements "optionmenu" widget. I am facing a problem that i have given six values in the tuple but when i select another option rather than "Gmail", i see only five values in the dropdown. can anyone tell me my mistake?  </p>
  
  <pre><code>from Tkinter import *
  import ttk
  
  root = Tk()
  
  choices = ("Gmail", "Outlook/Hotmail", "Yahoo", "Comcast", "AT&amp;T", "Verizon")
  dropdown_var = StringVar()
  dropdown_var.set(choices[0]) # set default value
  
  def data(*args):
      value = dropdown_var.get()
      print(value)
  
  l = ttk.Label(root, text="Select your e-mail provider : ")
  l.pack(side="left")
  
  option = ttk.OptionMenu(root, dropdown_var, *choices)
  option.pack(side="left", padx=10, pady=10)
  
  b = ttk.Button(root, text="Click", command=data)
  b.pack(side="bottom")
  
  root.mainloop()
  </code></pre>