I have a requirement that has a need for an ID in the OptGroup, which is currently not being generated.
Here's a fix for the ExtendedListbox.cs for the WriteOptionsGroup method:
/// <summary>
...
Id #6848 | Release:
None
| Updated: Jan 15 2009 at 8:24 AM by ra00l | Created: Dec 23 2008 at 4:10 PM by CitizenBane