title: Why the message "There are no trusted identity providers" in Sharepoint 2010 if it has a STS
body: <p>When you create a new web application in Sharepoint 2010 and you select "Claims based authentication" for the Authentication option, the "Trusted Identity provider" box is greyed out.</p>
  
  <p>There are some blogs etc. about how you add a custom STS or something like ADFS, but isn't the built-in Sharepoint STS an identity provider?</p>
  
  <p>What part does the Sharepoint STS play in a web application? Is it a different type of STS?</p>
  
  <p>In a normal Windows Identity Foundation (WIF) application that has a trust relationship with a STS, you get a login screen provided by the STS.  </p>
  
  <p>In Sharepoint 2020, you don't get any login screen?</p>
  
  <p>Are Sharepoint claims enabled applications different to WIF claims enabled applications?</p>