diff -r bddec2fad94e editor.settings.storage/src/org/netbeans/modules/editor/settings/storage/preferences/PreferencesImpl.java
--- a/editor.settings.storage/src/org/netbeans/modules/editor/settings/storage/preferences/PreferencesImpl.java	Mon Aug 04 17:37:54 2008 -0700
+++ b/editor.settings.storage/src/org/netbeans/modules/editor/settings/storage/preferences/PreferencesImpl.java	Mon Aug 04 21:36:03 2008 -0700
@@ -137,7 +137,11 @@
             putValueJavaType.set(String.class.getName());
         }
         try {
-            super.put(key, value);
+            synchronized(lock) {
+                if(key != null && value != null && value.equals(getSpi(key)))
+                    return;
+                super.put(key, value);
+            }
         } finally {
             if (putValueJavaType.get().equals(String.class.getName())) {
                 putValueJavaType.remove();