title: Backpress to previous fragment in another activity
body: <p>It seems each activity has its own Fragment Manager but I have a situation when I need to access the Fragment Manager of a previous activity. Here is the situation. I have tabs A - E launching Activities A - E in each tab. Each activity have fragments. So I am in Fragment B1 (in Activity B launched by Fragment A3 of Activity A) and I want to go back to A3 but since A3 is in another Activity, I can't use popBackStack on BackPress because Activity B doesn't know (can't access) the BackStack of Activity A. How do I get back to A3 of Activity A from B1 of Activity B. Thanks</p>