--- a/dwtx/dwtxhelper/Collection.d	Sat Nov 15 09:20:02 2008 +0100
+++ b/dwtx/dwtxhelper/Collection.d	Sun Feb 01 19:41:13 2009 +0100
@@ -235,17 +235,21 @@
     }
 
 class HashMap : Map {
+    //FIXME "NULL" is used to work around tango ticket 1468.
+    static Object NULL;
     // The HashMap  class is roughly equivalent to Hashtable, except that it is unsynchronized and permits nulls.
     alias tango.util.container.HashMap.HashMap!(Object,Object) MapType;
     private MapType map;
 
     public this(){
+        if( NULL is null ) NULL  = new Object();
         map = new MapType();
     }
     public this(int initialCapacity){
         this();
     }
     public this(int initialCapacity, float loadFactor){
+        if( NULL is null ) NULL  = new Object();
         map = new MapType(loadFactor);
     }
     public this(Map m){
@@ -263,7 +267,8 @@
         return containsKey(stringcast(key));
     }
     public bool containsValue(Object value){
-        return map.contains(value);
+        Object v = (value is null) ? NULL : value;
+        return map.contains(v);
     }
     public Set  entrySet(){
         HashSet res = new HashSet();
@@ -289,6 +294,7 @@
     }
     public Object get(Object key){
         if( auto v = key in map ){
+            if( *v is NULL ) return null;
             return *v;
         }
         return null;
@@ -310,11 +316,12 @@
         return res;
     }
     public Object put(Object key, Object value){
+        Object v = (value is null) ? NULL : value;
         Object res = null;
         if( auto vold = key in map ){
             res = *vold;
         }
-        map[ key ] = value;
+        map[ key ] = v;
         return res;
     }
     public Object put(String key, Object value){
@@ -328,13 +335,15 @@
     }
     public void   putAll(Map t){
         foreach( k, v; t ){
-            map[k] = v;
+            Object vi = (v is null) ? NULL : v;
+            map[k] = vi;
         }
     }
     public Object remove(Object key){
         if( auto v = key in map ){
             Object res = *v;
             map.remove(key);
+            if( res is NULL ) return null;
             return res;
         }
         map.remove(key);
@@ -773,7 +782,7 @@
         return res;
     }
     public override int opEquals(Object o){
-        if( auto other = cast(HashMap) o ){
+        if( auto other = cast(TreeMap) o ){
             if( other.size() !is size() ){
                 return false;
             }