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?
Set:
(setq mouse-autoselect-window t)
Answering the shift+arrow comment, do in your .emacs:
(windmove-default-keybindings)
来源：https://stackoverflow.com/questions/898401/how-to-get-focus-follows-mouse-over-buffers-in-emacs