HI there,

it's really confusing that how it is picking values by using {!filterId}
expression selectList component???

<apex:page standardController="Case" recordSetvar="cases">
    <apex:pageBlock >
        <apex:form id="theForm">
            <apex:panelGrid columns="2">
                <apex:outputLabel value="View:"/>
                <apex:selectList value="{!filterId}" size="1">
                    <apex:actionSupport event="onchange" rerender="list"/>
                    <apex:selectOptions value="{!listviewoptions}"/>
                </apex:selectList>
            </apex:panelGrid>
            <apex:pageBlockSection >
                <apex:dataList var="c" value="{!cases}" id="list">
                    {!c.subject}
                </apex:dataList>
            </apex:pageBlockSection>
        </apex:form>
    </apex:pageBlock>
</apex:page>

if anyone knows it there than please update me..... thanks.. in advance :)