title: Identity 3.1 - when changing email the user name gets changed, can this be avoided?
body: <p>A default <em>ASP .NET Core 3.1 Identity</em> mixes the email and user name pretty much together. I separated them in the <em>Login</em> and <em>Registration</em> pages by spawning them into my project and modifying them manually. But <em>Change email</em> sets the user name to the new email. Can I use some global flag to fix that strange behaviour? If not, which pages do I need to spawn and modify manually to get it right?</p>