•  Generally you can mark a type or member with the System.Diagnostics.DebuggerNonUserCode attribute to tell Visual Studio to ignore an exception thrown by your code.  Unfortunately, if you add it to the code here the problem still persists, so we likely also forgot to mark up the base class.  We'll open a bug report for this.
• You can also have Visual Studio ignore this exception by adding "IdeaBlade.EntityModel.LoginException" to the Debug | Exceptions window.  Add the exception to the "Common Language Runtime Exceptions" list, and un-check the User-unhandled check box. 
• You can also try out the LoginException functionality without the debugger (i.e., start without debugging).  This will show you how your users will see the feature, but isn't very useful since you probably do want to debug.

}

protected override bool ValidateUserCore(ILoginCredential credential) {

// Base class calls Membership.ValidateUser, and returns t/f based on whether

// the user is authenticated. If not authenticated, we don't actually know why.

// The base class does not throw a LoginException if the user is not authenticated,

// so we do here.

bool isAuthenticated = base.ValidateUserCore(credential);

if (isAuthenticated) return isAuthenticated;

var members = Membership.FindUsersByName(credential.UserName);

if (members.Count == 0) {

throw new LoginException(LoginExceptionType.InvalidUserName, "Invalid username");

} else {

throw new LoginException(LoginExceptionType.InvalidPassword, "Invalid password");

}

}