How to login in to SQL Server repo via design studio with Windows Authentication in Sagent Data Flow

When user name and password on login screen of the design studio are blank, Design studio logs in the repo using windows authentication.
Windows login used for this authentication is same as user who launched design studio. So, if I'm logged in, the machine with a user domain\user1 , design studio will use domain\user1 for windows authentication.

In case one is logged into machine using domain\user1 but wants to login in to Sagent repo with domain\user2, you will need to run saisd(Design studio) with a different user2.

For Windows 7, it can be via shift->right click on saisd.exe->run as different user.
UPDATED:  November 15, 2017