Index: applications/editors/josm/plugins/opendata/src/org/openstreetmap/josm/plugins/opendata/core/gui/ModulePreference.java
===================================================================
--- applications/editors/josm/plugins/opendata/src/org/openstreetmap/josm/plugins/opendata/core/gui/ModulePreference.java	(revision 29936)
+++ applications/editors/josm/plugins/opendata/src/org/openstreetmap/josm/plugins/opendata/core/gui/ModulePreference.java	(revision 29937)
@@ -45,4 +45,5 @@
 import org.openstreetmap.josm.gui.preferences.SubPreferenceSetting;
 import org.openstreetmap.josm.gui.preferences.TabPreferenceSetting;
+import org.openstreetmap.josm.gui.util.GuiHelper;
 import org.openstreetmap.josm.gui.widgets.SelectAllOnFocusGainedDecorator;
 import org.openstreetmap.josm.plugins.opendata.core.OdConstants;
@@ -309,11 +310,16 @@
 
         protected void alertNothingToUpdate() {
-            HelpAwareOptionPane.showOptionDialog(
-                    pnlModulePreferences,
-                    tr("All installed modules are up to date. JOSM does not have to download newer versions."),
-                    tr("Modules up to date"),
-                    JOptionPane.INFORMATION_MESSAGE,
-                    null // FIXME: provide help context
-            );
+            GuiHelper.runInEDTAndWait(new Runnable() {
+                @Override
+                public void run() {
+                    HelpAwareOptionPane.showOptionDialog(
+                            pnlModulePreferences,
+                            tr("All installed modules are up to date. JOSM does not have to download newer versions."),
+                            tr("Modules up to date"),
+                            JOptionPane.INFORMATION_MESSAGE,
+                            null // FIXME: provide help context
+                    );
+                }
+            });
         }