Inserting an imported document with InsertRange() throws an exception if the imported document contains hyperlinks

[dox-osksih]

Expected Behavior

Goal: import PDF file B and insert its pages to PDF file A. B may contain hyperlinks.

The pages from B should be inserted to A with the hyperlinks intact.

Actual Behavior

The line

PDFsharp/src/foundation/src/PDFsharp/src/PdfSharp/Pdf/PdfDictionary.cs

Line 1278 in 5fbf6ed

_elements.Add(key, value);

attempts to add a duplicate key to a dictionary. The following exception is thrown, the import fails and no document is produced:

System.ArgumentException: 'An item with the same key has already been added. Key: /Annots'

Steps to Reproduce the Behavior

Builds: all three PDFSharp builds present in the issue submission template.

Version: 6.2.0-preview-1.

MCVE: Issue.zip. The MCVE includes two simple PDF files with which the issue can be demonstrated.