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.
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?
What part does the Sharepoint STS play in a web application? Is it a different type of STS?
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.
In Sharepoint 2020, you don't get any login screen?
Are Sharepoint claims enabled applications different to WIF claims enabled applications?