[whatwg] Selectable category tree, nested optgroups?

[Oldřich Vetešník]

Hi,

Imagine you have a (for example) category tree like this:

* Cars
   * Sporty
   * Limo
     * 18 wheeler
   * Bloody good
   * Big
* Places to live in
   * Villa
   * Flat
   * Under bridge
...

and you are to select one for your article of some sort. <optgroup> isn't  
capable of doing this at the moment as it cannot be nested and you cannot  
select "Cars" category (it's its label attribute). Currently this is done  
by intending with spaces and, in my humble opinion, it doesn't look too  
accessible - I wouldn't want to crawl through it with my screenreader if  
it was a longer list.

I'm here to ask if there is/could be a better way than intending.

Thanks,
Ollie.