Save all buffers on focus lost

core/prelude-editor.el

@@ -186,6 +186,14 @@ The body of the advice is in BODY."
 
 (add-hook 'mouse-leave-buffer-hook 'prelude-auto-save-command)
 
+;; Autosave buffers when focus is lost
+(defun prelude-save-all-buffers ()
+  "Save all modified buffers, without prompts."
+  (save-some-buffers 'dont-ask))
+
+(when (version<= "24.4" emacs-version)
+  (add-hook 'focus-out-hook 'prelude-save-all-buffers))
+
 ;; highlight the current line
 (global-hl-line-mode +1)