Asp.Net Identity: Can't remove user from a role. Is this a bug or ...?

hi

The following code adds user to a role ( in other words, RoleManager.Update adds an entry intoAspNetUserRoles table )

var role = RoleManager.FindByName("roleName");
var user = UserManager.FindById("userName" );


IdentityUserRole userRole = new IdentityUserRole();
userRole.RoleId = role.Id;
userRole.UserId = user.Id;

role.Users.Add(userRole);
RoleManager.Update(role); // adds user to a role

 I'd also expect the following code to remove user from a role, but instead nothing happens ( in other words,RoleManager.Update should remove an entry from AspNetUserRoles table, but it doesn't ). Is this a bug or ...?

var role = RoleManager.FindByName("roleName");
var user = UserManager.FindById("userName" );

 
IdentityUserRole userRole = new IdentityUserRole();
userRole.RoleId = role.Id;
userRole.UserId = user.Id;

 
role.Users.Remove(userRole);
RoleManager.Update(role); // nothing happens

Btw:  The following code does remove user from a role:

UserManager.RemoveFromRole(user.Id, role.Name);

thank you