I have created a new VF page. In my VF page having Stage picklist same as Opportunity. If we select "Closed Won" then i need to make one a "Invoice selcetion" to editable, if we choose any other value in the picklist then "Invoice Selection" should be readable. I am trying this but didn't get any solution for this, using Salesforce PE. Kindly send any link for this to achieve. Thanks in advance, waiting for your reply.