NopContext.Current.User always null

Hi,

I have a quick question.
what is the difference between  "NopContext.Current.User"  and "NopContext.Current.Session.Customer"

I have replaced the code and Login Control for the CustomerLogin located at:  "\NopCommerceStore\Modules\CustomerLogin.ascx"

the reason to replacement is CustomerLogin.ascx is using Login Control but I need a Ajax popup inside Login Control that's not working so I have replaced the Login Control with custom textboxes and called the "CustomerManager.Login(username, password)" method to authenticate and store the user  session in database.

But on successfully login I always got  NopContext.Current.User as null  but NopContext.Current.Session.Customer is not null .


So Can anybody please let me know what methods are called for Builtin Login Control to set  "NopContext.Current.User"

I am using NOP V1.8