Masters hidden in vss are visible after converting to vssx

When converting vss to vssx, some masters that were initially hidden are now visible.

vss file and a screenshot of the issue:
extra masters.zip (406.3 KB)

The file was converted using this part of code:

File file = new File(PATH_TO_VSS_FILE);
Diagram d = new Diagram(file.getAbsolutePath());
d.save(file.getAbsolutePath() + "x", SaveFileFormat.VSSX);

@Denec
Thanks for the template file and screenshots.
We reproduced the problems you mentioned by converting your template vss file to vssx.
We have opened the following new ticket(s) in our internal issue tracking system and will deliver their fixes according to the terms mentioned in Free Support Policies.

Issue ID(s): DIAGRAMNET-53240

You can obtain Paid Support Services if you need support on a priority basis, along with the direct access to our Paid Support management team.

The issues you have found earlier (filed as DIAGRAMNET-53240) have been fixed in this update. This message was posted using Bugs notification tool by philip.zhou