title: ttk styling "TNotebook.Tab" background and borderwidth not working
body: <p>I been playing around with TKinter trying to create a multiple tab window.</p>
  
  <p>When I try to style the <code>TNotebook.Tab</code> it ignores the options <code>background</code> and <code>borderwidth</code>, but it acknowledges <code>foreground</code>. What am I doing wrong?</p>
  
  <p>Here is the relevant part of the code: </p>
  
  <pre><code>COLOR_1 = 'black'
  COLOR_2 = 'white'
  COLOR_3 = 'red'
  COLOR_4 = '#2E2E2E'
  COLOR_5 = '#8A4B08'
  COLOR_6 = '#DF7401'
  
  #Notebook Style
  noteStyler = ttk.Style()
  noteStyler.configure("TNotebook", background=COLOR_1, borderwidth=0)
  noteStyler.configure("TNotebook.Tab", background=COLOR_1, foreground=COLOR_3, lightcolor=COLOR_6, borderwidth=0)
  noteStyler.configure("TFrame", background=COLOR_1, foreground=COLOR_2, borderwidth=0)
  
  #Create Notebook and Tabs
  note = ttk.Notebook(gui, style='TNotebook')
  myTab = ttk.Frame(note, style='TFrame')
  note.add(myTab, text = 'MyTab', compound=tk.TOP)        
  note.pack(anchor=tk.W)
  </code></pre>
  
  <p>Here is an image of what the window looks like:</p>
  
  <p><img src="https://i.stack.imgur.com/bDQiV.png" alt="enter image description here"></p>
  
  <p>In case it matters, I'm running python 2.7 on Windows 7 64-bit.</p>