I have created a custom column with SharePoint and it appears to be working nicely.
I have created a document library and added to it a document set content type. This document set has the custom column call "TestColumn". This document set I also allow other content types that share this custom column.
Now in the customization of the document set you can specify that the certain columns share values. When you do this, AND edit a document within the document set only non-shared fields are displayed. Conversely, if you edit the parent container (the document set) you will see the custom field(s) for edit.
The PROBLEM..is my custom column is displayed at the document set level (correctly) AND at the document level within the document set. The custom column because it is shared with the document set should not be visible for edit/change at the item level.
Anyone have this issue?