(defconst mime-edit-split-ignored-field-regexp
"\\(^Content-\\|^Subject:\\|^Mime-Version:\\|Message-Id:\\)")
-(defvar mime-edit-split-blind-field-regexp
- "\\(^[BDFbdf]cc:\\|^cc:[ \t]*$\\)")
+(defcustom mime-edit-split-blind-field-regexp
+ "\\(^[BDFbdf]cc:\\|^cc:[ \t]*$\\)"
+ "*Regular expression to match field-name to be ignored when split sending."
+ :group 'mime-edit
+ :type 'regexp)
(defvar mime-edit-split-message-sender-alist nil)