Problem: How to Use Plain Enum as UPROPERTY in UE4

Problem

UBT would complain when we mark plain enum as UPROPERTY.

Version

Unreal Engine 4.20.3

Solution

Enclose plain enum type with TEnumAsByte. For example:

UPROPERTY(EditDefaultsOnly)
TEnumAsByte<EMyPlainEnum> PlainEnum;