Sorry, forget what I wrote two messages up. It works, but they gets logged in with the case they wrote. Not very good, so I made another approach. Find the two lines in wp-login.php:
if ( $user_login && $user_pass ) {
$user = new WP_User(0, $user_login);
Put this line between them:
$user_login_tmp = $wpdb->get_var("SELECT user_login FROM $wpdb->users WHERE user_login LIKE '$user_login'");
if ( !$user_login_tmp == '' ) $user_login = $user_login_tmp;
And you might wish to add trim to password and userlogin. When people copy and paste, a space is often at the end.
$user_login = trim(sanitize_user( $user_login ));
$user_pass = trim($_POST['pwd']);
Hopefully this is a “final solution” ??
Dgold; I have a line “Write nothing here” on my blog. A few people wrote the word nothing there…