Two browser instances at the same time

Yes, the same page and user.  The test goal is to verify that when one user is doing an specific action on that page (seting a textbox for instance), another user can't do the action (setting the same textbox) because the application blocks some actions when some user is doing it.



So the same browser, two windows, two users doing the same action. User 1 can set the textbox, user 2 has the textbox disabled.