Usability: Reduce the number of clicks / actions to add a nested element.
[DMN Designer] Data Types tab - Add a nested row to a new Structured data type by default
Increase the advanced user productivity when he creates a new Data Type
DMN Data Types Insert Field is Not Clear
DMN Editor: Data type usability study
DMN Editor Data type usability study: design assets
DMN data type editor enhancements based on usability findings