Hi Jonas,
This is controlled through standard configuration. Where, your field display in Material Master can be controlled through configuration based on Material Type.
To see that use TCode OMS9 - Field selection for data screen (or IMG - Logistics General - Material Master - Field Selection - Maintain Field Selection for Data Screens).
Loading Group - MARC-LADGR is part of field selection group 94(TCode OMSR or IMG - Logistics General - Material Master - Field Selection - Assign Fields to Field Selection Groups).
Hope that helps you.
Thanks, JP