Hi Hieudt,
Thank you for the update.
We have validated the provided sample and the reported scenario occurred due to your CustomCell renderer customization for ComboBox. In your custom renderer, you have used foreach loop in GetlistFromArray() and SetSuggestedChoices() method. In order to overcome this scenario, we would suggest that you to use linq queries to get the specified items from the data source.
Please get back to us if you need any other assistance.
Regards,
Arulpriya