Hi Alban,
Thank you for using Syncfusion products.
The above reported feature Sorting is currently implemented and included in out latest version 9.4.0.62.
The above reported feaure is not include in the old version 4.4.0.51.
We recommend you to upgrade to the latest version to include this feature.
Latest Version link:
http://www.syncfusion.com/downloads/latest-versionPlease let me know if you require any further clarificatinos.
Thanks,
Sridhar.s