I can not fgure out how to make live unwrap work in new Blender. The only checkbox I can find is in UV Editor -> UV menu, but marking it changes nothing. There is not checkbox like this in 3D Viewport -> UV menu, there is nothing in 3d Viewport -> U context menu. I simply can not find it. I was googling it but without any useful result. What happened there? Is this a bug? Have it been removed? Am I missing some plugin? Am I doing something wrong? Any help will be appreciated.