Hi all!
I have a facelet page, with one form and input fields and with this:
...
<h:inputText id="tradeId" value="#{model.tradeId}" required="true"/>
<a4j:region>
<a4j:commandButton id="generate" value="#{msg['button.generate.tradeid']}"
action="#{controller.generateTradeId}"
reRender="tradeId"/>
</a4j:region>
...
You have a deal with standard JSF behavior. The data for input component is not updated from model if submitted value presents in the component tree.
Try to add ajaxSingle="true" to a4j:commandButton