Index: /applications/editors/josm/plugins/wikipedia/src/org/wikipedia/WikidataTagCellRenderer.java
===================================================================
--- /applications/editors/josm/plugins/wikipedia/src/org/wikipedia/WikidataTagCellRenderer.java	(revision 32719)
+++ /applications/editors/josm/plugins/wikipedia/src/org/wikipedia/WikidataTagCellRenderer.java	(revision 32720)
@@ -9,8 +9,7 @@
 import java.util.Locale;
 import java.util.Map;
-import java.util.concurrent.Callable;
+import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ExecutionException;
-import java.util.concurrent.Future;
 import java.util.stream.Collectors;
 
@@ -20,27 +19,10 @@
 
 import org.openstreetmap.josm.Main;
+import org.openstreetmap.josm.gui.util.GuiHelper;
 import org.openstreetmap.josm.tools.Utils;
 
 public class WikidataTagCellRenderer extends DefaultTableCellRenderer {
 
-    final Map<String, Future<String>> labelCache = new ConcurrentHashMap<>();
-
-    static class LabelLoader implements Callable<String> {
-        final String id;
-        JTable table;
-
-        public LabelLoader(String id, JTable table) {
-            this.id = id;
-            this.table = table;
-        }
-
-        @Override
-        public String call() throws Exception {
-            final String label = WikipediaApp.getLabelForWikidata(id, Locale.getDefault());
-            table.repaint();
-            table = null;
-            return label;
-        }
-    }
+    private final Map<String, CompletableFuture<String>> labelCache = new ConcurrentHashMap<>();
 
     @Override
@@ -70,13 +52,13 @@
     protected JLabel renderValues(Collection<String> ids, JTable table, JLabel component) {
 
-        ids.stream()
-                .filter(id -> !labelCache.containsKey(id))
-                .forEach(id -> {
-                    labelCache.put(id, Main.worker.submit(new LabelLoader(id, table)));
-                });
+        ids.forEach(id ->
+                labelCache.computeIfAbsent(id, x ->
+                        CompletableFuture.supplyAsync(() -> WikipediaApp.getLabelForWikidata(x, Locale.getDefault())))
+        );
 
         final Collection<String> texts = new ArrayList<>(ids.size());
         for (String id : ids) {
             if (!labelCache.get(id).isDone()) {
+                labelCache.get(id).thenRun(() -> GuiHelper.runInEDT(table::repaint));
                 return null;
             }