A group cannot contain both model and detail (view-specific) elements. If you select both types of elements and then try to group them, the detail elements are placed into an attached detail group for that model group. 
-  In the drawing area, do one of the following: 
  - Select model elements and detail elements, simultaneously. Click Modify | Multi-Select tab Create panel Create panel  (Create Group). (Create Group).
- Select view-specific elements, tags, or dimensions that are associated with an existing model group, and click Modify | <Elements> tab Create panel Create panel  (Create Group). (Create Group).
- Select an existing model group, and click Modify | Model Groups tab Group panel Group panel Edit Group. Click Edit Group panel Edit Group. Click Edit Group panel  (Attach). (Attach).
 
- In the Create Model Group and Attached Detail Group dialog, enter a name for the model group (if necessary), and enter a name for the attached detail group. 
- Click OK. 
 
In the Project Browser, the attached detail group displays under the model group that it belongs to. 
 
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