If "no selection" is not universally supported by the different views, I
think it would be better to not support it. Even if we disallow "no
selection" a user can still get it by using a Python None for the value and
"none" for the label. I would rather handle the "no selection" feature
using that = an explicit selection indicating None.


On Tue, Feb 4, 2014 at 8:36 AM, Jonathan Frederic
<notifications@github.com>wrote:

> In IPython/html/widgets/widget_selection.py:
>
> >          if self.value_lock.acquire(False):
> >              try:
> > -                if new in self.labels:
> > -                    self.value = self.values[self.labels.index(new)]
> > +                if new in self.values:
> > +                    self.value = self.values[new]
> >                  else:
> >                      self.value = None
>
> I think it makes sense to allow no selection, but I don't believe the
> front-end supports that yet. The RadioButtons will probably never support
> nothing selected- but the ToggleButtons, Select, and Dropdown could all
> support it one way or another.
>
> --
> Reply to this email directly or view it on GitHub<https://github.com/ipython/ipython/pull/5012/files#r9427322>
> .
>



-- 
Brian E. Granger
Cal Poly State University, San Luis Obispo
bgranger@calpoly.edu and ellisonbg@gmail.com