RelationList dialog causes very severe performance issues

[nyurik]

In file josm/core/src/org/openstreetmap/josm/gui/dialogs/RelationListDialog.java line 151:

displaylist.addListSelectionListener(e -> updateActionsRelationLists());

Whenever I try to fetch Wikidata IDs for a large set of relations, JOSM freezes, sometimes for hours, with 100% CPU on a single thread. Debugging showed that all the work is being done in the above function. If I close the RelationList dialog, it finishes in seconds. I tried it in 11362 (svn build)

Repo: Install wikipedia plugin, and get 1000+ objects using this query. Select all relations, and "fetch Wikidata IDs" (Data menu).

[out:xml][timeout:50];
(
    relation["wikipedia"]({{bbox}});
);
out meta;

[skyper]

Thanks for your report, however your ticket is incomplete and therefore not helpful in its current form.

Please add all needed information according to this list:

• The required parts of the Status Report from your JOSM.
  • Please, use Report Bug from Help menu and copy & paste.
• Describe what behaviour you expected.
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