diff --git a/tapestry-core/src/main/java/org/apache/tapestry5/internal/services/LocalizationSetterImpl.java b/tapestry-core/src/main/java/org/apache/tapestry5/internal/services/LocalizationSetterImpl.java
index 58ebb33..bacf40b 100644
--- a/tapestry-core/src/main/java/org/apache/tapestry5/internal/services/LocalizationSetterImpl.java
+++ b/tapestry-core/src/main/java/org/apache/tapestry5/internal/services/LocalizationSetterImpl.java
@@ -193,7 +193,7 @@
 
     public boolean isSupportedLocaleName(String localeName)
     {
-        return supportedLocaleNames.contains(localeName);
+        return supportedLocaleNames.contains(localeName.toLowerCase());
     }
 
     public SelectModel getSupportedLocalesModel()
diff --git a/tapestry-core/src/test/java/org/apache/tapestry5/internal/services/LocalizationSetterImplTest.java b/tapestry-core/src/test/java/org/apache/tapestry5/internal/services/LocalizationSetterImplTest.java
index e1222a9..f72c1d1 100644
--- a/tapestry-core/src/test/java/org/apache/tapestry5/internal/services/LocalizationSetterImplTest.java
+++ b/tapestry-core/src/test/java/org/apache/tapestry5/internal/services/LocalizationSetterImplTest.java
@@ -205,4 +205,28 @@
         verify();
 
     }
+   
+    @Test
+    public void is_supported_locale_name()
+    {
+        PersistentLocale pl = mockPersistentLocale();
+        ThreadLocale tl = mockThreadLocale();
+        Request request = mockRequest();
+
+
+        replay();
+
+        LocalizationSetterImpl setter = new LocalizationSetterImpl(request, pl, tl, "de, de_DE, de_CH,en");
+
+        assertTrue(setter.isSupportedLocaleName("de"));
+        assertTrue(setter.isSupportedLocaleName("de_de"));
+        assertTrue(setter.isSupportedLocaleName("de_de"));
+        assertTrue(setter.isSupportedLocaleName("de_DE"));
+        assertTrue(setter.isSupportedLocaleName("de_ch"));
+        assertTrue(setter.isSupportedLocaleName("de_CH"));
+        assertTrue(setter.isSupportedLocaleName("en"));
+
+        verify();
+
+    }
 }