how to get focus-follows-mouse over buffers in emacs?

Question

Suppose I have a source file open and I launch a shell. I can hit C-x o to switch between the two buffers. But how can I get it so that when I move the mouse the buffer under the mouse gets focus, just like the "focus follows mouse" option common in window managers?

Answer 1

Set:

(setq mouse-autoselect-window t)

Answer 2

Answering the shift+arrow comment, do in your .emacs:

(windmove-default-keybindings)