Use
Documents which you created in your project documentation lose their assignment to IMG structure nodes when these nodes no longer exist (e.g. after an update). The documentation exists, but you cannot access it directly.
The document assignment function lists all documents which are not assigned to a structure node. You can assign the listed documents to any IMG structure node.
Procedure
All documents with no assignment to a structure node are displayed in the Invisible documents list. You can display selected documents with the Display note symbol.
The IMG structure is displayed in a new window.
The row is highlighted.
The node text appears in the IMG activity column next to the document ID.
Result
You can now call the assigned documentation from the IMG structure and it no longer appears in the list of invisible documents.