title: How to left align widget label in iPython 3?
body: <p>How can I left align, rather than right align, the label in an iPython 3 widget, such as IntSlider? My ultimate goal is to left align a set of labeled widgets. This entails left aligning their labels, since the label is the leftmost element of each widget.</p>
  <p>I've read the discussion in
  <a href="https://stackoverflow.com/questions/26534123/aligning-textbox-widgets-in-ipython-notebooks">Aligning TextBox Widgets in IPython Notebooks</a>, but (a) it focuses on making more space for a right-aligned label, and (b) the proposed solution does not seem to affect the label width. (As an aside, I would be interested in finding cell-executable code that can reset the minimum label width.)</p>
  <p>I've also read the discussion in <a href="https://stackoverflow.com/questions/27114757/change-the-size-of-the-label-in-an-ipython-notebook-widget">Change the size of the label in an IPython notebook widget</a>, but it doesn't seem to offer a simple solution.</p>
  <p>Thanks for your help.</p>
  <h3>Addendum (2015-06-02):</h3>
  <p>Looks like widget.interactive() does not play nicely with the solution suggested by Jakob. Example:</p>
  <pre class="lang-py prettyprint-override"><code>from IPython.html import widgets
  from IPython.display import display
  def mySlider(text='', twidth=100, min=0, max=10, value=5):
      c1 = widgets.HBox()
      ints = widgets.IntSlider(min=min, max=max, value=value)
      text = widgets.HTML(text, width=twidth)
      c1.children = (text, ints)
      return c1
  
  s1 = mySlider('Test')
  s2 = mySlider('TestTest')
  s3 = mySlider('TestTestTest')
  
  def process(a, b, c):
      print([a, b, c])
  
  widgets.interactive(
      process,
      a=s1.children[1].value,
      b=s2.children[1].value,
      c=s3.children[1].value
  )
  </code></pre>
  <p>yields slider labels a, b, c with the usual alignment.</p>