+(defcustom notmuch-show-height-limit nil
+ "Height (from leaves) beyond which message bodies are displayed lazily.
+
+If bound to an integer, any message with height in the message
+tree greater than this will have its body displayed lazily,
+initially only a button.
+
+If this variable is set to nil (the default) no such lazy
+display is done."
+ :type '(choice (const :tag "No limit" nil)
+ (number :tag "Limit" 10))
+ :group 'notmuch-show)
+