+(defcustom notmuch-show-imenu-indent nil
+ "Should Imenu display messages indented.
+
+By default, Imenu (see Info node `(emacs) Imenu') in a
+notmuch-show buffer displays all messages straight. This is
+because the default Emacs frontend for Imenu makes it difficult
+to select an Imenu entry with spaces in front. Other imenu
+frontends such as counsel-imenu does not have this limitation.
+In these cases, Imenu entries can be indented to reflect the
+position of the message in the thread."
+ :type 'boolean
+ :group 'notmuch-show)
+