Listview Button Selected values not showing on repeat

Hello i have this visualpage:

<apex:page standardController="Opportunity" 
  recordSetVar="opportunities" cache="true">
    <apex:pageBlock title="Selected Opportunities" id="muselectedlist">
       <apex:pageBlockTable value="{!selected}" var="opp" id="mutab">
       <apex:column value="{!opp.name}" id="oppname"/>
       <apex:column value="{!opp.stagename}" id="oppstage"/>
       </apex:pageBlockTable>
    </apex:pageBlock>
</apex:page>

I use it in a custom button list view, i select 1 or more record and click the button, but none of the records are displayed in my page. Anyone know why?

Thanks,

André