Describe the bug

A (large) model that opens in v2.22 does not open in v2.23.

Gaphor version: 2.23.0
Operating System: Darwin (21.6.0)
Display: GdkMacosDisplay
Python version: 3.11.7
GTK version: 4.12.4
Adwaita version: 1.4.2
GtkSourceView version: 5.10.0
Cairo version: 1.18.0
Pango version: 1.50.14
PyGObject version: 3.46.0
Pycairo version: 1.25.1
pygit2/libgit2 version: 1.13.3 / 1.7.1

Errors:

Time since application startup: 0:00:55
|Traceback (most recent call last):
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphor/ui/errorhandler.pyc", line 42, in response
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphor/ui/filemanager.pyc", line 234, in
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphor/core/eventmanager.pyc", line 83, in handle
| File "/Applications/Gaphor.app/Contents/Frameworks/generic/event.pyc", line 61, in handle
|ExceptionGroup: Error while handling events (1 sub-exception)
└─┬──────────────────────────────╌┄┈
|Traceback (most recent call last):
| File "/Applications/Gaphor.app/Contents/Frameworks/generic/event.pyc", line 57, in handle
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphor/application.pyc", line 119, in on_session_shutdown
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphor/application.pyc", line 147, in shutdown_session
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphor/application.pyc", line 231, in shutdown
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphor/application.pyc", line 238, in shutdown_service
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphor/core/modeling/elementfactory.pyc", line 76, in shutdown
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphor/core/modeling/elementfactory.pyc", line 197, in flush
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphor/core/modeling/diagram.pyc", line 362, in unlink
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphas/connections.pyc", line 165, in remove_connections_to_item
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphas/connections.pyc", line 148, in _disconnect_item
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphor/diagram/_connector.pyc", line 108, in call
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphor/UML/classes/containmentconnect.pyc", line 68, in disconnect
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphor/core/modeling/element.pyc", line 213, in setattr
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphor/core/modeling/properties.pyc", line 149, in set
| File "/Applications/Gaphor.app/Contents/Frameworks/gaphor/core/modeling/properties.pyc", line 381, in set
|TypeError: Can not set <gaphor.UML.uml.Package element b0d8bd42-2066-11ee-b860-ba28606445aa>.package to itself
└─────────────────────────────╌┄┈

Expected behavior

The model to open. Or to identify the issue, so it can be corrected.

OS

• Linux (Please put in notes the specific distro)
• [x ] macOS
• Windows

Version

Version of Gaphor:2.23

Additional information

The model opens in 2.22, is there a way to identify the problematic elements?