strange behaviour of onchange event

[jamesjmp]

I have a selectOneMenu that has a default option by means of a f:selectItem and several options by means of f:selectItems.
It works ok. I want an action to be fired when the user selects a different option. I´ve done it with a4j:support event onchange without problem.
The matter is that I have tested that the event is not fired when you choose the f:selectItem option, and it works ok whenever you choose some of the values provided by the f:selectItems.
This is the code:

            <s:decorate id="domBuySellSei" template="layout/edit.xhtml"  
            rendered="#{internationalOrderManager.getSettlementInstructionsList().size() ne 0}">
                    <ui:define name="label">#{messages['view.SettlementInstruction']}</ui:define>
                    <h:selectOneMenu id="counterpart" value="#{internationalOrderManager.settlementInstruction}"
                        required="true"
                        label="#{messages['SettlementInstruction']}">
                        <f:converter converterId="boleta.SettlementInstructionConverter" />
                        <f:selectItem itemLabel="--- Please select an option ---"
                            />
                        <f:selectItems value="#{internationalOrderManager.getSettlementInstructionsItems()}"/>
                        <a4j:support event="onchange"
                            action="#{internationalOrderManager.setDefaultSettlementInstruction()}"
                            reRender="infoSetIns,editableSetInsField,update" ajaxSingle="true" />
                    </h:selectOneMenu>
            </s:decorate>

Imagine that

                        <f:selectItems value="#{internationalOrderManager.getSettlementInstructionsItems()}"/>

returns ten options. If I select one of them, the event is fired, but when I select Please select an option nothing happens, and action defined in the a4j:support event onchange is not launched.
any idea?

[drevil]

Hi. If you only need one additional selectItem then I wold suggest using the "s" prefix (xmlns:s="http://jboss.com/products/seam/taglib"). This way you can use:

<s:selectItems value="#{internationalOrderManager.getSettlementInstructionsItems()}" noSelectionLabel="--- Please select an option ---"/>

[niox.nikospara.yahoo.com]

Your <h:selectOneMenu> is required! Therefore processing stops at the validation JSF phase, without invoking your code.

Why don't you try specifying a non-null value for the <f:selectItem>? You are then responsible for filtering this value in your code.