1. I use the same method when I need a single wall in place of a splinted wall.
2. Not one but two:
-one in the default program: Plan->Join Walls (Ctrl+Alt+J)
-second (if you have installed Advanced editing plugin): Plan->Connect walls.
Both need to have at least 2 walls selected.
Look similar but each have also some different results.
Generally will connect the end of the first selected wall with the start of the second.