User generated content, based Symfony forms, only supports a subset of FieldTypes at the moment (TextBlock, TextLine, Checkbox and Selection).

Make sure:

• FormMapper classes provide form definition for content and settings editing
• DataTransformers handle data conversion from/to Symfony fields value format
• forms are rendered according to EZP-27578
• only Required validator is utilized from Symfony Forms, other validators can be omitted as FieldType definition already provides validation