h:selectOneRadio selection gets unselected - ajax

Question

I have a table that uses a radio button to select a row. When the radiobutton is clicked ajax executes some code to update another field and then render the form. Everything works fine, except that the radio selection disappears and all the radio buttons are unselected. I'm not sure why this is happening? The button was clicked so the value shouldn't change. And it's not the onchange javascript, I removed that as a test and still the same problem. I also can't just render the updated field because it's separate from the code below, I get a servlet exception - unknown id error (maybe someone could tell me how to get around that also?)
<h:dataTable id="addClient" styleClass="dataTable"
value="#{AddEntryMB.clientValues}" var="c" binding="#{AddEntryMB.dataTable}"
rendered="#{AddEntryMB.renderClientTable}">
<f:facet name="header" >
Select Client to Associate with Appointment
</f:facet>
<h:column>
<f:facet name="header">Select</f:facet>
<h:selectOneRadio valueChangeListener="#{AddEntryMB.setSelectedItem}"
immediate="true" onchange="dataTableSelectOneRadio(this);" >
<f:selectItem itemValue="null" />
<f:ajax event="click" render="#form"/>
</h:selectOneRadio>
</h:column>

Answer 1

Look like the value of your selection isn't saved in the backing bean.
First you should bind your h:selectOneRadio component to a backing bean value:
<h:selectOneRadio valueChangeListener="#{AddEntryMB.setSelectedItem}"
value=#{c.radioValue}
immediate="true" onchange="dataTableSelectOneRadio(this);" >
then try to process the dataTable within your ajax like:
<f:ajax event="click" render="#form" execute="addClient"/>
Also I would also add an itemLabel beside itemValue to see what is selected:
<f:selectItem itemValue="null" itemLabel="NULL"/>

Answer 2

It gets unselected because the value is not been set in a model value and the form get refreshed by ajax. You could prevent the unselection by binding the value to the model.
<h:selectOneRadio ... value="#{AddEntryMB.selected[c.id]}">
with
private Map<Long, Boolean> selected = new HashMap<Long, Boolean>(); // +getter
In this example, I assume that the type represented by #{c} has a private Long id property which represents the unique ID.