I Tried with the following code .But the page is opening in new tab

<apex:page standardController="Case" extensions="GEHCIT_Case_Buttons">
<apex:pageMessages id="msgs"/>
 <apex:includeScript value="/soap/ajax/26.0/connection.js"/>
<apex:includeScript value="/support/console/25.0/integration.js"/>

        function testOpenSubtab(url2) {
            //First find the ID of the primary tab to put the new subtab in
            var PBID=sforce.console.getEnclosingPrimaryTabId();

            sforce.console.focusSubtabByNameAndPrimaryTabName('00006487','Test Account');
            var SBId=null;
              var SBId=sforce.console.getFocusedSubtabId();
            var id='{!id}';
                       var url=url2+id;
            sforce.console.getEnclosingPrimaryTabId(function openSubtab(result){
            var primaryTabId = result.id;
         sforce.console.openSubtab(primaryTabId ,url ,true,'Email',SBId);
        });
             
        }

<apex:form>
<apex:commandButton onClick="testOpenSubtab('/apex/GE_HCIT_Send_Email?id=');return false" value="SendEmail" rendered="{!Case.SVMXC__Is_Entitlement_Performed__c=true}" />
</apex:form>
</apex:page>

Hi all,
I have loaded account details in visualforce page through pageblock table, if data exceeds the page it has to show scroll down, if i scroll down the column headers should not be scroll down.
Bellow is my code. and what lines i need to add for bellow code.
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<apex:page standardController="Account" recordSetVar="rcst">
    <apex:form >
        <apex:pageBlock title="Accounts" >
            <div style="overflow: auto; height: 200px;" layout="block" position ="fixed">
                <apex:pageblockTable value="{!rcst}" var="a" headerClass="headerStyle" width="100%">
                    <apex:column value="{!a.Id}" ></apex:column>
                    <apex:column value="{!a.Name}" ></apex:column>
                    <apex:column value="{!a.type}" ></apex:column>
                    <apex:column value="{!a.industry}"></apex:column>
                <apex:inlineEditSupport />
                </apex:pageblockTable>
            </div>                                        
        </apex:pageBlock>
    </apex:form>
</apex:page>

Thanks.