ToggleButtons description width doesn't change with `style` kwarg

Following the docs here I’m trying to change the width of the description of a ToggleButtons by passing in a style kwarg. This works for an IntSlider as in the docs, but not for a ToggleButtons.

If someone can point me towards the relevant parts of IntSlider and ToggleButtons I’m happy to tag a stab at fixing this myself.

MWE:

from ipywidgets import IntSlider, ToggleButtons
from IPython.display import display

style = {'description_width': 'initial'}

# description reads 'A too long ...'
display(IntSlider(description='A too long description'))

# description reads 'A too long description'
display(IntSlider(description='A too long description', style=style))  

 # description reads 'A too long ...'
display(ToggleButtons(description='A too long description', options=['a','b'], style=style)) 

Versions:

{'commit_hash': 'd86648c5d',
 'commit_source': 'installation',
 'default_encoding': 'UTF-8',
 'ipython_path': '/Users/hhinnefeld/miniconda3/lib/python3.5/site-packages/IPython',
 'ipython_version': '6.1.0',
 'os_name': 'posix',
 'platform': 'Darwin-16.6.0-x86_64-i386-64bit',
 'sys_executable': '/Users/hhinnefeld/miniconda3/bin/python',
 'sys_platform': 'darwin',
 'sys_version': '3.5.2 |Continuum Analytics, Inc.| (default, Jul  2 2016, '
                '17:52:12) \n'
                '[GCC 4.2.1 Compatible Apple LLVM 4.2 (clang-425.0.28)]'}

ipykernel==4.6.1
ipython==6.1.0
ipython-genutils==0.2.0
ipywidgets==7.0.0
jupyter-client==5.1.0
jupyter-console==5.1.0
jupyter-core==4.3.0

[hinnefe2]

Hey yeah, sorry to leave it hanging, I’ll have a go at it tonight.

[jasongrout]

Fixed by #1714.