diff --git a/posts/Ask_for_selection_in_emacs_addendum.mdwn b/posts/Ask_for_selection_in_emacs_addendum.mdwn
new file mode 100644
index 0000000..169eba8
--- /dev/null
+++ b/posts/Ask_for_selection_in_emacs_addendum.mdwn
@@ -0,0 +1,20 @@
+I erroneously assumed (and thought I tested) that using `tmm-prompt`
+could be done the way I described before. The `oni:mailbox-map`
+variable needs to be a little different from what I'd shown before,
+namely:
+
+[[!format el """
+(defvar oni:mailbox-map
+  '("top" ("menu" ("ryulash.org" . "ryu")
+           ("ninthfloor" . "ninthfloor")
+           ("gmail" . "gmail")
+           ("aethon" . "aethon")))
+  "A mailbox map for use with `tmm-prompt'.")
+"""]]
+
+Without the *top* and *menu* items it will complain about wrong
+arguments.
+
+[[!meta date="2012-05-02 21:52:00"]]
+[[!meta title="Ask for selection in emacs, addendum"]]
+[[!tag emacs elisp coding]]