diff --git a/libs/yscript/javascript.cpp b/libs/yscript/javascript.cpp
index aa3c4ebb..9e277251 100644
--- a/libs/yscript/javascript.cpp
+++ b/libs/yscript/javascript.cpp
@@ -187,7 +187,7 @@ private:
 	JsFunction* func, bool constr) const;
     bool callFunction(ObjList& stack, const ExpOperation& oper, GenObject* context,
 	long int retIndex, JsFunction* func, ObjList& args,
-	ExpOperation* thisObj, ExpOperation* scopeObj) const;
+	JsObject* thisObj, JsObject* scopeObj) const;
     inline JsFunction* getGlobalFunction(const String& name) const
 	{ return YOBJECT(JsFunction,m_globals[name]); }
     long int m_label;
@@ -2090,7 +2090,11 @@ bool JsCode::callFunction(ObjList& stack, const ExpOperation& oper, GenObject* c
 	Debug(this,DebugWarn,"Oops! Could not find return point!");
 	return false;
     }
-    ExpOperation* thisObj = constr ? popOne(stack) : 0;
+    ExpOperation* op = constr ? popOne(stack) : 0;
+    JsObject* thisObj = YOBJECT(JsObject,op);
+    if (thisObj && !thisObj->ref())
+	thisObj = 0;
+    TelEngine::destruct(op);
     ObjList args;
     JsObject::extractArgs(func,stack,oper,context,args);
     return callFunction(stack,oper,context,index,func,args,thisObj,0);
@@ -2098,11 +2102,11 @@ bool JsCode::callFunction(ObjList& stack, const ExpOperation& oper, GenObject* c
 
 bool JsCode::callFunction(ObjList& stack, const ExpOperation& oper, GenObject* context,
 	long int retIndex, JsFunction* func, ObjList& args,
-	ExpOperation* thisObj, ExpOperation* scopeObj) const
+	JsObject* thisObj, JsObject* scopeObj) const
 {
     pushOne(stack,new ExpOperation(OpcFunc,0,retIndex,true));
     if (scopeObj)
-	pushOne(stack,new ExpWrapper(scopeObj,scopeObj->name()));
+	pushOne(stack,new ExpWrapper(scopeObj,"()"));
     JsObject* ctxt = JsObject::buildCallContext(func->mutex(),thisObj);
     for (unsigned int idx = 0; ; idx++) {
 	const String* name = func->formalName(idx);
@@ -2188,10 +2192,18 @@ ScriptRun::Status JsRunner::call(const String& name, ObjList& args,
 	TelEngine::destruct(scopeObj);
 	return Failed;
     }
+    JsObject* jsThis = YOBJECT(JsObject,thisObj);
+    if (jsThis && !jsThis->ref())
+	jsThis = 0;
+    JsObject* jsScope = YOBJECT(JsObject,scopeObj);
+    if (jsScope && !jsScope->ref())
+	jsScope = 0;
+    TelEngine::destruct(thisObj);
+    TelEngine::destruct(scopeObj);
     reset();
     // prepare a function call stack
     ExpOperation oper(ExpEvaluator::OpcFunc,name,args.count());
-    if (!c->callFunction(stack(),oper,this,-1,func,args,thisObj,scopeObj))
+    if (!c->callFunction(stack(),oper,this,-1,func,args,jsThis,jsScope))
 	return Failed;
     mylock.drop();
     // continue normal execution like in run()
diff --git a/libs/yscript/jsobjects.cpp b/libs/yscript/jsobjects.cpp
index 450ca41e..719dce77 100644
--- a/libs/yscript/jsobjects.cpp
+++ b/libs/yscript/jsobjects.cpp
@@ -209,10 +209,10 @@ void JsObject::printRecursive(const GenObject* obj)
     Output("%s",buf.c_str());
 }
 
-JsObject* JsObject::buildCallContext(Mutex* mtx, ExpOperation* thisObj)
+JsObject* JsObject::buildCallContext(Mutex* mtx, JsObject* thisObj)
 {
     JsObject* ctxt = new JsObject(mtx,"()");
-    if (thisObj)
+    if (thisObj && thisObj->ref())
 	ctxt->params().addParam(new ExpWrapper(thisObj,"this"));
     return ctxt;
 }
diff --git a/libs/yscript/yatescript.h b/libs/yscript/yatescript.h
index 6cb4b0ac..dd40e558 100644
--- a/libs/yscript/yatescript.h
+++ b/libs/yscript/yatescript.h
@@ -1805,7 +1805,7 @@ public:
      * @param thisObj Optional object that will be set as "this"
      * @return New empty object usable as call context
      */
-    static JsObject* buildCallContext(Mutex* mtx, ExpOperation* thisObj = 0);
+    static JsObject* buildCallContext(Mutex* mtx, JsObject* thisObj = 0);
 
     /**
      * Initialize the standard global objects in a context
diff --git a/modules/javascript.cpp b/modules/javascript.cpp
index f0d42d62..ddff1343 100644
--- a/modules/javascript.cpp
+++ b/modules/javascript.cpp
@@ -482,12 +482,12 @@ void JsEngine::initialize(ScriptContext* context)
 
 bool JsMessage::runAssign(ObjList& stack, const ExpOperation& oper, GenObject* context)
 {
+    XDebug(&__plugin,DebugAll,"JsMessage::runAssign '%s'='%s'",oper.name().c_str(),oper.c_str());
     if (ScriptContext::hasField(stack,oper.name(),context))
 	return JsObject::runAssign(stack,oper,context);
     if (!m_message)
 	return false;
-    ExpWrapper* w = YOBJECT(ExpWrapper,&oper);
-    if (w && !w->object())
+    if (JsParser::isUndefined(oper))
 	m_message->clearParam(oper.name());
     else
 	m_message->setParam(new NamedString(oper.name(),oper));
@@ -1019,8 +1019,12 @@ bool JsAssist::init()
 	    ExpWrapper wrap(jsm,"message");
 	    chan->runAssign(m_runner->stack(),wrap,m_runner);
 	}
-	if (jsm && jsm->ref())
+	if (jsm && jsm->ref()) {
+	    JsObject* cc = JsObject::buildCallContext(ctx->mutex(),jsm);
+	    ExpEvaluator::pushOne(m_runner->stack(),new ExpWrapper(cc,cc->toString(),true));
+	    jsm->ref();
 	    ExpEvaluator::pushOne(m_runner->stack(),new ExpWrapper(jsm,"(message)"));
+	}
     }
     if (!m_runner->callable("onLoad"))
 	return true;