diff --git a/web/CXM_web_arg_utils.anubis b/web/CXM_web_arg_utils.anubis
index f33dd6e..8037ed2 100644
--- a/web/CXM_web_arg_utils.anubis
+++ b/web/CXM_web_arg_utils.anubis
@@ -29,23 +29,70 @@ public define One
   lwa <- [ w_arg . *lwa]
 .
 
+define List(Web_arg)
+  _remove_web_arg
+  (
+    List(Web_arg) lwa,
+    String        arg_name
+  )=
+  if lwa is
+  {
+    []      then  [],
+    [h . t] then
+      if h is web_arg(name, _) then
+        if name = arg_name then
+          t
+        else
+          [h . _remove_web_arg(t, arg_name)]
+      else
+        [h . _remove_web_arg(t, arg_name)]
+  }
+.
+
 public define One
   remove_web_arg
   (
     Var(List(Web_arg))  lwa,
     String              arg_name
   )=
-  lwa <- map_select((Web_arg w_arg) |-> if w_arg is web_arg(name, value) then if name = arg_name then failure else success(w_arg) else success(w_arg), *lwa)
+  lwa <- _remove_web_arg(*lwa, arg_name)
+.
+
+define List(Web_arg)
+  _replace_web_arg
+  (
+    List(Web_arg) lwa,
+    String        arg_name,
+    String        value
+  )=
+  if lwa is
+  {
+    []      then  /*println("arg_name "+arg_name+" not found, add it");*/[web_arg(arg_name, value)],
+    [h . t] then
+      if h is web_arg(name, _) then
+        if name = arg_name then
+          [web_arg(name, value) . t]
+        else
+          [h . _replace_web_arg(t, arg_name, value)]
+      else
+        [h . _replace_web_arg(t, arg_name, value)]
+  }
 .
 
 public define One
+/* replace the value of given web argument name in the list. Replace the value of the first found
+ * argument.
+ * If the web argument is not found, an entry is created for this WEB argument name with given 
+ * value
+ */
   replace_web_arg
   (
-    Var(List(Web_arg))  lwa,
-    String              arg_name,
-    String              value
+    Var(List(Web_arg))  lwa,        //current list of web argument
+    String              arg_name,   //web argument name to replace
+    String              value       //value to replace
   )=
-  lwa <- map_select((Web_arg w_arg) |-> if w_arg is web_arg(name, value) then if name = arg_name then success(web_arg(name, value)) else success(w_arg) else success(w_arg), *lwa)
+  //println("replace web arg name "+arg_name+" value "+value);
+  lwa <- _replace_web_arg(*lwa, arg_name, value)
 .
 
   
--
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