If I put into the rich:comboBox an empty string like this:

<rich:comboBox id="combo" valueChangeListener="#{scopedBean.changemetod}" >
<f:selectItem itemValue=""/>
<f:selectItem itemValue="2"/>
<f:selectItem itemValue="3"/>
<f:selectItem itemValue="4"/>
</rich:comboBox>

the suggestion list appears with only one row, insted if i put the empty string in this other way:

<rich:comboBox id="combo" valueChangeListener="#{scopedBean.changemetod}" >
<f:selectItem itemValue="2"/>
<f:selectItem itemValue="3"/>
<f:selectItem itemValue="4"/>
<f:selectItem itemValue=""/>
<a4j:support event="onselect" reRender="out"> </a4j:support>
</rich:comboBox>

it appears well...

Any one know why?