diff --git a/SOPE/NGCards/iCalTimeZone.m b/SOPE/NGCards/iCalTimeZone.m
index 310983c94..510db0759 100644
--- a/SOPE/NGCards/iCalTimeZone.m
+++ b/SOPE/NGCards/iCalTimeZone.m
@@ -49,6 +49,7 @@ static NSArray *knownTimeZones;
 + (void) initialize
 {
   cache = [[NSMutableDictionary alloc] init];
+  knownTimeZones = nil;
 }
 
 + (iCalTimeZone *) timeZoneForName: (NSString *) theName
@@ -124,9 +125,7 @@ static NSArray *knownTimeZones;
   NSRange ext;
   BOOL b;
 
-  timeZoneNames = knownTimeZones;
-
-  if (!timeZoneNames)
+  if (!knownTimeZones)
     {
       timeZoneNames = [NSMutableArray new];
 
@@ -156,11 +155,11 @@ static NSArray *knownTimeZones;
 		}
 	    }
 	}
-      knownTimeZones = [timeZoneNames sortedArrayUsingSelector: @selector (localizedCaseInsensitiveCompare:)];
+      knownTimeZones = [NSArray arrayWithArray: timeZoneNames];
       [knownTimeZones retain];
     }
 
-  return timeZoneNames;
+  return knownTimeZones;
 }
 
 - (Class) classForTag: (NSString *) classTag
diff --git a/UI/PreferencesUI/UIxPreferences.m b/UI/PreferencesUI/UIxPreferences.m
index 8b47046a5..bb087356e 100644
--- a/UI/PreferencesUI/UIxPreferences.m
+++ b/UI/PreferencesUI/UIxPreferences.m
@@ -153,7 +153,7 @@
 
 - (NSArray *) timeZonesList
 {
-  return [iCalTimeZone knownTimeZoneNames];
+  return [[iCalTimeZone knownTimeZoneNames] sortedArrayUsingSelector: @selector (localizedCaseInsensitiveCompare:)];
 }
 
 - (NSString *) userTimeZone