title: Combobox values appearing as single string characters
body: <p>I am new posting to the forums &amp; utilizing python/tkinter in order to create an electronic form to gather issues from manufacturing floor.</p>
  
  <p>I have a (2) comboboxes. </p>
  
  <p>The 1st combobox gains its "values" from a given dictionary.keys() which updates the "values" of a 2nd combobox. However, when selecting the values for the 2nd combobox after selecting for the 1st combobox, the values only show singular characters from the dictionary.values().</p>
  
  <p>Here is the list from the txt file. The first item on each line is the key, while the rest of the items on the same line are its values.</p>
  
  <pre><code>Bondshop, Plies: Layup Difficulty, Plies: Cutting Edge
  IB Postbond, POU, Equipment, Inspection, Available Work Space, Big Paint, 1575, QN
  General Postbond, Inspection
  Seal Area, Inspection
  Big Paint, Inspection
  Deflash, Inspection
  </code></pre>
  
  <p>Why does my 2nd combobox appear as so? See below.</p>
  
  <p><a href="http://i.stack.imgur.com/3C5wZ.png" rel="nofollow">"...show singular characters"...</a></p>
  
  <pre><code>===snip===
      def loadcategory(self):
  
           # Reads production areas &amp; cateogries from dictCategory.txt file
           self.textfileCategory = open('dictCategory.txt', 'r')
           self.lines_category = self.textfileCategory.readlines()
           for line in self.lines_category:
               splitLine = line.split(',')
               dict_category[str(splitLine[0])] = ",".join(splitLine[1:])
           self.textfileCategory.close()
  
  ===snip===  
  
      def UpdateData(self, event):
  
          # Updates Category Combobox based on Production Area selection
          self.menu_category.set('---')
          category = self.menu_production_area.get()
          self.menu_category['values'] = sorted(dict_category[category])
  
  ===snip===
  
      self.menu_production_area = ttk.Combobox(Main_Frame, state='readonly', values = sorted(list(dict_category.keys())), width=25)
      self.menu_production_area.bind('&lt;&lt;ComboboxSelected&gt;&gt;', self.UpdateData)
      self.menu_production_area.grid(row=2, column=1, sticky='w')
  </code></pre>