Index: generic/xotcl.c
===================================================================
diff -u -r5a0750dc422574bc5ae91d9b58c64b8f5713d405 -r7afa0b7f3e63e10eb45a65a7360285ba9590f514
--- generic/xotcl.c	(.../xotcl.c)	(revision 5a0750dc422574bc5ae91d9b58c64b8f5713d405)
+++ generic/xotcl.c	(.../xotcl.c)	(revision 7afa0b7f3e63e10eb45a65a7360285ba9590f514)
@@ -6236,42 +6236,41 @@
 static int convertToSwitch(Tcl_Interp *interp, Tcl_Obj *objPtr, XOTclParam CONST *pPtr, ClientData *clientData) {
   return convertToBoolean(interp, objPtr, pPtr, clientData);
 }
-static int convertToObject(Tcl_Interp *interp, Tcl_Obj *objPtr, XOTclParam CONST *pPtr, ClientData *clientData) {
-  if (GetObjectFromObj(interp, objPtr, (XOTclObject **)clientData) == TCL_OK)
-    return TCL_OK;
-  return XOTclObjErrType(interp, objPtr, "object");
-}
-static int convertToClass(Tcl_Interp *interp, Tcl_Obj *objPtr,  XOTclParam CONST *pPtr, ClientData *clientData) {
-  if (GetClassFromObj(interp, objPtr, (XOTclClass **)clientData, 0) == TCL_OK) {
-    return TCL_OK;
-  }
-  return XOTclObjErrType(interp, objPtr, "class");
-}
-static int convertToObjectOfType(Tcl_Interp *interp, Tcl_Obj *objPtr, XOTclParam CONST *pPtr, ClientData *clientData) {
-  XOTclObject *object;
+static int objectOfType(Tcl_Interp *interp, XOTclObject *object, Tcl_Obj *objPtr, XOTclParam CONST *pPtr) {
   XOTclClass *cl;
-  Tcl_Obj *valueObj = pPtr->converterArg;
   Tcl_DString ds, *dsPtr = &ds;
-
-  if (valueObj == NULL)
-    return XOTclVarErrMsg(interp, "No object type specified", (char *) NULL);
-
-  if ((GetObjectFromObj(interp, objPtr, &object) == TCL_OK)
-      && (GetClassFromObj(interp, valueObj, &cl, 0) == TCL_OK)
+  
+  if (pPtr->converterArg == NULL) 
+    return TCL_OK;
+    
+  if ((GetClassFromObj(interp, pPtr->converterArg, &cl, 0) == TCL_OK)
       && isSubType(object->cl, cl)) {
-    *clientData = object;
     return TCL_OK;
   }
 
   DSTRING_INIT(dsPtr);
   Tcl_DStringAppend(dsPtr, "object of type ", -1);
-  Tcl_DStringAppend(dsPtr, ObjStr(valueObj), -1);
+  Tcl_DStringAppend(dsPtr, ObjStr(pPtr->converterArg), -1);
   XOTclObjErrType(interp, objPtr, Tcl_DStringValue(dsPtr));
   DSTRING_FREE(dsPtr);
 
   return TCL_ERROR;
 }
 
+static int convertToObject(Tcl_Interp *interp, Tcl_Obj *objPtr, XOTclParam CONST *pPtr, ClientData *clientData) {
+  if (GetObjectFromObj(interp, objPtr, (XOTclObject **)clientData) == TCL_OK) {
+    return objectOfType(interp, (XOTclObject *)*clientData, objPtr, pPtr);
+  }
+  return XOTclObjErrType(interp, objPtr, "object");
+}
+
+static int convertToClass(Tcl_Interp *interp, Tcl_Obj *objPtr,  XOTclParam CONST *pPtr, ClientData *clientData) {
+  if (GetClassFromObj(interp, objPtr, (XOTclClass **)clientData, 0) == TCL_OK) {
+    return objectOfType(interp, (XOTclObject *)*clientData, objPtr, pPtr);
+  }
+  return XOTclObjErrType(interp, objPtr, "class");
+}
+
 static int convertToRelation(Tcl_Interp *interp, Tcl_Obj *objPtr,  XOTclParam CONST *pPtr, ClientData *clientData) {
   /* XOTclRelationCmd is the real setter, which checks the values
      according to the relation type (Class, List of Class, list of
@@ -6395,12 +6394,9 @@
     paramPtr->flags |= XOTCL_ARG_RELATION;
     /*paramPtr->type = "tclobj";*/
   } else if (length >= 6 && strncmp(option, "type=", 5) == 0) {
-    if (paramPtr->converter != NULL &&
-        paramPtr->converter != convertToObject && 
+    if (paramPtr->converter != convertToObject && 
         paramPtr->converter != convertToClass) 
       return XOTclVarErrMsg(interp, "option type= only allowed for object or class", (char *) NULL);
-    paramPtr->converter = NULL;
-    result = ParamOptionSetConverter(interp, paramPtr, option, convertToObjectOfType);
     paramPtr->converterArg = Tcl_NewStringObj(option+5, length-5);
     INCR_REF_COUNT(paramPtr->converterArg);
   } else {
Index: tests/parameters.xotcl
===================================================================
diff -u -r5a0750dc422574bc5ae91d9b58c64b8f5713d405 -r7afa0b7f3e63e10eb45a65a7360285ba9590f514
--- tests/parameters.xotcl	(.../parameters.xotcl)	(revision 5a0750dc422574bc5ae91d9b58c64b8f5713d405)
+++ tests/parameters.xotcl	(.../parameters.xotcl)	(revision 7afa0b7f3e63e10eb45a65a7360285ba9590f514)
@@ -53,21 +53,27 @@
 #                  specified value is the first argument unless "noarg" is used  
 #                  (example: -noinit).
 #
-# parameter type   multivalued  required  noarg   arg=  valueCheck  methodParm   objectParm
-#  substdefault       NO         NO         NO    NO      NO           YES         YES (autmatically set by -parameter on []}
-#  initcmd            NO         YES        NO    NO      NO        NO/POSSIBLE    YES
-#  method             NO         YES        YES   YES     NO        NO/POSSIBLE    YES
+# parameter type   multivalued  required  noarg  type=   arg=  valueCheck  methodParm   objectParm
+#  substdefault       NO         NO         NO    NO      NO      NO           YES         YES (autmatically set by -parameter on []}
+#  initcmd            NO         YES        NO    NO      NO      NO        NO/POSSIBLE    YES
+#  method             NO         YES        YES   NO      YES     NO        NO/POSSIBLE    YES
 #
-#  relation           NO         YES        NO    YES     NO           NO          YES
-#  stringtype         YES        YES        NO    NO      YES          YES         YES
+#  relation           NO         YES        NO    NO      YES     NO           NO          YES
+#  stringtype         YES        YES        NO    NO      NO      YES          YES         YES
 #
-#  switch             NO         NO         NO    NO      NO           YES         YES
-#  integer            YES        YES        NO    NO      YES          YES         YES    
-#  boolean            YES        YES        NO    NO      YES          YES         YES
-#  object             YES        YES        NO    NO      YES          YES         YES
-#  class              YES        YES        NO    NO      YES          YES         YES
-#  objectOfType       YES        YES        NO    NO      YES          YES         YES
-#  userdefined        YES        YES        NO    YES     YES          YES         YES
+#  switch             NO         NO         NO    NO      NO      NO           YES         YES
+#  integer            YES        YES        NO    NO      NO      YES          YES         YES    
+#  boolean            YES        YES        NO    NO      NO      YES          YES         YES
+#  object             YES        YES        NO    YES     NO      YES          YES         YES
+#  class              YES        YES        NO    YES     NO      YES          YES         YES
+#
+#  userdefined        YES        YES        NO    NO      YES     YES          YES         YES
+#
+# tclObj + converterArg (alnum..xdigit)            Attribute ... -type alnum
+# object + converterArg (some class, e.g. ::C)     Attribute ... -type ::C    Attribute -type object -arg ::C
+# class + converterArg (some metaclass, e.g. ::M)                             Attribute -type class -arg ::M
+#
+# todo: get rid of convertToObjectOfType() merge to convertToClass/Object
 
 #::xotcl::Slot {
 #     {name "[namespace tail [::xotcl::self]]"}