Feature for optgroups

[pimduijst]

Hi,

I would like to know if I am missing a feature in the docs or that it is not available yet. Would it be possible to also show returned data in an optgroup?

Something like this:

<optgroup label="Client A">
<option value="location_id">Location Foo</option>
<option value="some_location_id">Location Bar</option>
<option value="another_location_id">Location Foobar</option>
</optgroup>`
<optgroup label="Client B">
<option value="location_id">Location Foo</option>
<option value="some_location_id">Location Bar</option>
<option value="another_location_id">Location Foobar</option>
</optgroup>`

[markhalliwell]

Dup of #31