Index: trunk/src/org/openstreetmap/josm/gui/preferences/AdvancedPreference.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/preferences/AdvancedPreference.java	(revision 3028)
+++ trunk/src/org/openstreetmap/josm/gui/preferences/AdvancedPreference.java	(revision 3029)
@@ -110,4 +110,5 @@
         };
         final JTable list = new JTable(model);
+        list.putClientProperty("terminateEditOnFocusLost", true);
         list.getColumn(tr("Key")).setCellRenderer(renderer);
         JScrollPane scroll = new JScrollPane(list);