When looking at the "Discipline Sub-Grouping" topic in the What's New section of the delivered Help file, it shows a drop-down list with a number of entries. However, I am not seeing this list. Also, should there be discipline sub-group for Architecture; e.g., Doors, Windows, etc.?
The AECOsim Building Designer disciplines are system-defined into Architectural, Structural, Mechanical and Electrical, with Mechanical further sub-divided into HVAC, Plumbing, Fire Protection and LPG (Low Pressure Gas). The applicable subgroups are then displayed as folders within each discipline. While the delivered datasets include a few sub-groups for most disciplines, the Electrical discipline does not include any delivered Sub-Groups so if this is the one you had selected the list would be empty. Regarding the Architectural discipline, the delivered Sub-Groups include Openings, Specialty and Walls.
To create a new discipline sub-group, from within the DataGroup Catalog Editor right-click on the desired discipline name, select New Sub-Group, and enter a name.
Then drag & drop the Catalog Types that you would like directly into your new Sub-Group folder.
Note: Because each Catalog Type can (and in most cases, will) have a different list of DataGroup properties associated with them, there is no interface for moving Catalog Items between Catalog Types.