title: Failed to change font size in ipython qtconsole
body: <p>I tried to change the <code>ipython qtconsole</code> font size with reference to <a href="https://stackoverflow.com/a/18904744/2185472">this answer</a> in stackoverflow; however, the font size refused to change no matter how I change the <code>~/.ipython/profile_default/ipython_config.py</code>.</p>
  
  <pre><code>➜  ~  ipython profile locate
  /home/nick/.ipython/profile_default
  
  ➜  ~  head .ipython/profile_default/ipython_config.py 
  # Configuration file for ipython.
  c = get_config()    
  c.IPythonWidget.font_size = 16
  c.IPythonWidget.font_family = 'Source Code Pro'
  
  ➜  ~  uname -a
  Linux nick-thinkpad 4.2.5-1-ARCH #1 SMP PREEMPT Tue Oct 27 08:13:28 CET 2015 x86
  _64 GNU/Linux                                                                  
  
  ➜  ~  ipython --version
  4.0.0
  </code></pre>
  
  <p>To my suprise, <code>ipython qtconsole --ConsoleWidget.font_size=16</code> works. What's wrong with my configuration?</p>