Hi Ralf,
Thanks for your interest in Syncfusion Products.
We have checked with a sample for reproducing the issue regarding the ComboBoxAdv behavior change. We are unable to reproduce the issue. Could you please modify the sample or provide us the reproducing steps which would be helpful for us to provide you the better solution.
Please download the sample from the following.
[Sample Link]
http://www.syncfusion.com/uploads/redirect.aspx?file=WF-ComboBoxAdvIssue-74577_84fabd04.zip&team=developmentIn future please follow the Incident ID #74577 to have a better transaction.
Please let us know if you need any other details.
Regards,
Jeraldes