a-start a-end len-a
b-start b-end len-b
(bufa-modified (buffer-modified-p buf-a))
- (bufb-modified (buffer-modified-p buf-b))
+ (bufb-modified (and (not (eq buf-a buf-b)) (buffer-modified-p buf-b)))
(buf-a-read-only (with-current-buffer buf-a buffer-read-only))
(buf-b-read-only (with-current-buffer buf-b buffer-read-only))
temp-a temp-b)