Here some code to illustrate that:

My JSP:

<rich:panel id="decoderPanel">
 <f:facet name="header">
 <h:outputText value="myTitle"/>
 </f:facet>
 <a4j:commandLink value=""
 actionListener="#{proConManController.deviceSelected}">
 <h:graphicImage value="myImage" binding="myBinding" />
 </a4j:commandLink>
 <rich:dropSupport acceptedTypes="#{someType}"
 dropListener="#{controller.drop}"
 dropValue="#{someName}"
 ondrop="some Expression"/>
</rich:panel>

Here the relevant part from the dropListener:

public void drop(DropEvent event) {
 String dropValue = (String) event.getDropValue();
 Encoder encoder = getEncoderMap().get(dropValue);
 RmiQueue callSequence = new RmiQueue();

 AsyncRmiCall rmiCall = new AsyncRmiCall() {
 public void execute() {
 if (getBusinessDelegate().connect(encoder)) {
 encoder.setIsConnected(true);
 decoder.updateGUI();
 }

 protected RmiQueue getRmiQueue() {
 return callSequence;
 }
 };
 decoder.setImage(Configuration.IN_PROCESS);
 callSequence.enqueRmiCall(rmiCall);
}

It would be great to start rerendering again after calling the updateGUI method. Please help me!