Hi Steve,
Please refer to the following KB article instead :
How do I place a ComboBoxBase control within a PopupControlContainer such that the PopupControlContainer does not close when the ComboBoxBase’s popup is displayed?
I have created a
test sample accordingly that shows how you could use the ComboBoxAdv in the place of a ComboBoxBase. Please refer to the sample attached and let me know if you need further assistance. Thanks for your interest in Syncfusion products.
Regards,
Guru Patwal
Syncfusion, Inc.