Thanks alot Olivier for your post!

In JUDE, when you click on a composite item, you can see the property of the selected item in the Property View (the left bottom pane).

In JUDE/Professional, there is an option to see the
element of the selected composite that exist in other diagrams.
In the Diagram Editor (where you edit diagrams).
1. Right-click on the target element in the Diagram Editor.
2. Select [Show in Structure Tree] on Pop-Up Menu.
3. The target diagram is displayed and selected in the Structure Tree. (the left top lane)

This feature is not supported for component elements in JUDE/Professional 3.1 Beta versions. It is planned to be supported in 3.1 release at the end of this month!

Thank you.
Best regards,
-satomi