Hi Jonathan Blackburn,
Thanks for using EJ2 Syncfusion components.
We have checked the your reported issue (Once allowCustomValue is turned on the list stops being populated). We can’t able to reproduce that issue in our end. For your convenience, we have prepared the simple plunker sample.
If the issue persists, kindly provide us additional details like video to showcase the issue along with package version and browser details. If possible, please modify the above sample to reproduce the issue in our end so that we can proceed further.
Regards,
Thangavel E