[curt.clifton]

The first behavior (RC disappearing) sounds like a bug. Use Help → Send Feedback to report it. It's especially helpful to the devs if you can come up with steps that always cause the problem to happen.

Regarding focusing on contexts, you just have to select the context in the context mode sidebar and actions for the unselected contexts will be hidden. Then you can create a perspective, checking the Restore Selection box in the Perspective Window.