new file mode 100644
--- /dev/null
+++ b/.elisp/settings/80.fill-paragraph.el
@@ -0,0 +1,26 @@
+(defun kf-fill-paragraph (&optional justify)
+  "Like fill-paragraph, but don't mark the buffer as modified if no change.
+
+Emacs's native fill-paragraph is like the burglar who breaks into
+your house, rearranges all your furniture exactly as it was, and
+departs: even if the result of the fill is to leave the buffer in
+exactly the same state, it still marks the buffer as modified so you
+know you've been broken into.
+
+Note: to get this accepted into Emacs, it should watch the md5sum for
+just the affected region rather than the entire buffer.  See
+`fill-region' and `fill-region-as-paragraph' in textmodes/fill.el.
+The elegant solution would be a new macro, '(detect-buffer-unmodified
+from to)' or something, that just wraps the relevant body of code in
+those two functions.  Then it could be used by other fill functions
+easily too."
+  (interactive "P")
+  (let ((orig-md5sum (md5 (current-buffer)))
+        (was-modified-before-fill (buffer-modified-p)))
+    (fill-paragraph justify)
+    (let ((new-md5sum (md5 (current-buffer))))
+      (when (string-equal orig-md5sum new-md5sum)
+        (set-buffer-modified-p was-modified-before-fill)))))
+
+(if (eq (key-binding "\M-q") 'fill-paragraph)
+    (global-set-key "\M-q" 'kf-fill-paragraph))