Index: sbbs.el
==================================================================
--- sbbs.el
+++ sbbs.el
@@ -61,10 +61,14 @@
   :type 'boolean)
 
 (defcustom sbbs-open-at-last-post nil
   "Jump to last post in a thread when opening a thread."
   :type 'boolean)
+
+(defcustom sbbs-kill-threads-on-quit t
+  "Kill all thread buffers when quitting a board buffer."
+  :type 'boolean)
 
 (defface sbbs--semi-spoiler-face
   '((((background light)) :background "gray80" :foreground "black")
     (((background dark)) :background "gray20" :foreground "white"))
   "Face for spoiler text in threads.")
@@ -225,10 +229,18 @@
   (unless (and (eq 'highlight (get-text-property (point) 'face))
                (looking-at-p "\\`#[[:digit:]]+"))
     ;; in case we are on the first character of a post, we shouldn't
     ;; jump back, since that would mean setting to point to NR-1.
     (sbbs-read-previous 1)))
+
+(defun sbbs--cleanup-board ()
+  "Close all thread buffers for the current board."
+  (when sbbs-kill-threads-on-quit
+    (dolist (buf (buffer-list))
+      (when (and (eq (buffer-local-value 'sbbs--board buf) sbbs--board)
+                 (buffer-local-value 'sbbs--thread-id buf))
+        (kill-buffer buf)))))
 
 
 ;;; UI GENERATOR
 
 (defconst sbbs--link-regexp
@@ -755,10 +767,13 @@
 
   (setq tabulated-list-format [("Date" 16 t)
                                ("#" 3 t :right-align t)
                                ("Headline" 0 nil)]
         tabulated-list-sort-key '("Date" . t))
+  (add-hook 'quit-window-hook
+            'sbbs--cleanup-board
+            nil t)
   (add-hook 'tabulated-list-revert-hook
             #'sbbs--reload-board nil t)
   (tabulated-list-init-header)
 
   (hl-line-mode t))