Hi Ralf,
Could you please consider upgrading to latest version, it should resolve your issue. Our latest version can be downloaded from the below link
http://www.syncfusion.com/downloads/latestversion/default.aspxFor Unlock Key:
If you hold a Syncfusion license with a valid subscription, you can obtain your key for this version by visiting the "Download the latest versions" section within Direct-Trac and clicking on the appropriate key icon. If you're currently evaluating our products or considering renewing an expired subscription, please contact our sales team (salessupport@syncfusion.com) for the key and further details.
Regards,
Ajish.