For the project I’m working on, I don’t care so much about DX, since it’s to be cross platform. I’ve noticed that the GL rendering path has all the GUI stuff for tessellation shaders - you can play with the drop downs and so on - but they don’t actually work. Some forum browsing has led to the conclusion that indeed they are not yet implemented under the GL rendering path.
GL_ARB_tessellation_shader has been around for quite a while, so it isn’t a limitation of the API. It would be awesome to have this available on all platforms that can support it!