Issue with Self Contained Liferay Vaadin IPC Portlet

I have created a Self Contained Liferay Vaadin IPC portlet. It works well without making the portlets instanceable where there is one sender and receiver portlet on a page. Next , I made the portlets instanceable and made the eventId configurable so that I can have multiple sender and receiver portlets on a Page. But it is not working as it renders only one receiver portlet on a page when i send the request from two Sender portlets even though they have different event Ids. Can anyone please help me to fix it ?

Vaadin Version : 7.2
Liferay Version 6.2