Hi Richard,
Thanks for your patience.
At present there is no support to edit the Tabitem header from code behind by using IsTabEditing property and we have logged this as feature request.
As per our forum regulation, we will not be able to share this feature through forum.
However, if you are interested in receiving this feature then, we would request you to use our Direct-Trac Support system to get this feature and resolve all your technical queries.
For more details, please login into http://www.syncfusion.com/Account/ and we will be happy to help you.
Please let us know in case of any queries.
Regards,
Muthalagu