rendering apex:tab based on 'multi select' picklist

Question

I need to render visualforce tabs in a tabpanel based on whether a multiselect picklist field is selected. But not getting the tab to show/hide using the following (Revised) approach:

<apex:page standardStylesheets="true" standardController="Account_Summary__c" readOnly="false"  showHeader="true"  >
<apex:stylesheet value="{!URLFOR($Resource.pdfcssresource, 'CREresource_CRE.css')}"/>
<apex:form id="form1">
<apex:pageBlock id="block1"  >
<apex:actionRegion > 

<apex:pageBlockSection columns="1" id="section1" title="General Information" showHeader="true" >

    <apex:inputField value="{!Account_Summary__c.Lines_of_Business__c}" style="color:blue;" >
        <apex:actionSupport event="onchange" reRender="tab1a,tab1b,tab1c,theTabPanel" /> 
        </apex:inputField>          
    <apex:inputField value="{!Account_Summary__c.Other_Line_of_Business__c}"  style="color:blue;" rendered="{!CONTAINS(Account_Summary__c.Lines_of_Business__c,'Other')}" />'

</apex:pageBlockSection>

<apex:actionRegion immediate="true" >    
<apex:outputPanel >
<b><apex:outputText style="font-style:bold;color:blue" value="Line of Business Analysis" /></b>

<apex:tabPanel switchType="client" selectedTab="name2" id="theTabPanel">
<apex:tab label="TEST1" name="tab1a" id="tab1a" rendered="{!CONTAINS(Account_Summary__c.Lines_of_Business__c,'Workers Compensation')}" > </apex:tab>
<apex:tab label="TEST2" name="tab1b" id="tab1b" rendered="{INCLUDES(Account_Summary__c.Lines_of_Business__c,'Workers Compensation')}" > </apex:tab>
<apex:tab label="TEST3" name="tab1c" id="tab1c" rendered="{!IF(CONTAINS(Account_Summary__c.Lines_of_Business__c,'Workers Compensation'),"true","false")}"  > </apex:tab>

</apex:tabPanel>
</apex:outputPanel>
</apex:actionRegion>


</apex:actionRegion>
</apex:pageBlock>
</apex:form>
</apex:page>

Answer 1

You should use a CASE formula function. Please find the below example where Country__c is a picklist which contains different Country names.

<!-- Page: -->
<apex:page standardController="Book__c" id="thePage">
    <apex:form>
        <apex:inputField value="{!Book__c.Country__c}">
            <apex:actionSupport event="onchange" reRender="theTabPanel" />
        </apex:inputField>
    </apex:form>
    <apex:tabPanel switchType="client" selectedTab="name2" id="theTabPanel">
        <apex:tab label="One" name="name1" id="tabOne" rendered="{!CASE(Book__c.Country__c,"USA", "true","false")}">content for tab one</apex:tab>
        <apex:tab label="Two" name="name2" id="tabTwo">content for tab two</apex:tab>
    </apex:tabPanel>
</apex:page>

In your code the rendered attribute should be changed to this.

rendered="{!CASE(Account_Summary__c.Lines_of_Business__c,"Workers Compensation", "true","false")}"

If you using multi-select picklist you can use the CONTAINS function. In the below example multipicklist__c is a multi-select picklist which contains A,B,C,D E.

<!-- Page: -->
<apex:page standardController="Book__c" id="thePage">
    <apex:form>
        <apex:inputField value="{!Book__c.multipicklist__c}">
            <apex:actionSupport event="onchange" reRender="theTabPanel" />
        </apex:inputField>        
    </apex:form>
    <apex:tabPanel switchType="client" selectedTab="name2" id="theTabPanel">
        <apex:tab label="One" name="name1" id="tabOne">content for tab one</apex:tab>
        <apex:tab label="Two" name="name2" id="tabTwo" rendered="{!IF(CONTAINS(Book__c.multipicklist__c,"A") && CONTAINS(Book__c.multipicklist__c,"B"),"true","false")}" >content for tab two</apex:tab>
    </apex:tabPanel>
</apex:page>

Update code according to updated question.

<!-- Page: -->
<apex:page standardController="Book__c" id="thePage">
    <apex:form >
        <apex:pageBlock id="block1"  >
            <apex:actionRegion >
                <apex:pageBlockSection columns="1" id="section1" title="General Information" showHeader="true" >
                    <apex:inputField value="{!Book__c.multipicklist__c}">
                        <apex:actionSupport event="onchange" reRender="outputpanel" />
                    </apex:inputField> 
                </apex:pageBlockSection>
                <apex:actionRegion immediate="true" >
                    <apex:outputPanel id="outputpanel"  >
                        <apex:tabPanel  switchType="client" selectedTab="name2" rendered="{!CASE(Book__c.multipicklist__c,'A', 'true','false')}"  id="theTabPanel">
                            <apex:tab label="One" name="name1" id="tabOne">content for tab one</apex:tab>
                            <apex:tab label="Two" name="name2" id="tabTwo">content for tab two</apex:tab> 
                        </apex:tabPanel>
                    </apex:outputPanel>
                </apex:actionRegion>
            </apex:actionRegion>
        </apex:pageBlock>
    </apex:form>
</apex:page>