Handling concurrent call to conversational components on JBoss Seam

Question

I'm working on a project using JBoss Seam 2.2.6, JSF 1.2 and RichFaces 3.

Users of the application must enter data in a form, and for certain fields it is necessary to make calls to the backend to recalculate other values ​​based on the data entered.

Back-end calls are made using the AJAX support RichFaces offers, for example, using <a4j: support> for onchange events.

This is the Jsf/RichFaces code:

<h:selectOneMenu value="#{managedBean.someValue}" >
         <s:selectItems value="#{managedBean.entityList}" var="_item"
               label="#{_item.label}"
                itemValue="{item.value}"
           />
          <a4j:support 
                event="onchange"          //  handling onchange event
                status="waitStatus"       //  "please wait.." pop up blocks UI
                eventsQueue="afjQueue"    //  ajax requests queue
                ignoreDupResposes="true"  //  avoid similar requests
                action="#{managedBean.onInputChange()}"
                reRender="somePanel"
                oncomplete="showErrors();"
            />
</h:selectOneMenu>

The problem is that the user could click on different fields of the form or on different buttons, make multiple requests to the server in a short period of time, and Seam does not support concurrent calls to the same conversation scoped component (if it happened a ConcurrentCallToConversation error would occur )

To avoid this we have done the following:

1) adding a a4j:queue for queueing AJAX requests

2) setting ignoreDupResposes="true" to avoid "similar" requests.

3) setting seam core property concurrent-request-timeout="5000" (info about this property. This property causes a request to have exclusive control of the component for 5 seconds)

4) adding a a4j:status that shows a "please wait..." dialog between request starts and request ends, blocking the UI

Because the user experience is affected by a pop up that appears every time an ajax request is made, i want to delete the alternative 4.

So my question is: Is it guaranteed that there will not occur a concurrent call to conversation if I use a queue of requests and a large enough timeout for exclusive access? meaning that using the first 3 items would be enough.