+subject matches this regexp, search parent message by subject matching.
+If nil, never search search parent by subject."
+ :type '(choice string
+ (const :tag "Don't search parent" nil))
+ :group 'wl-summary)
+
+;;; Mark & Action
+(defcustom wl-summary-mark-action-list
+ '(("*"
+ target-mark
+ nil
+ wl-summary-register-target-mark
+ nil
+ wl-highlight-summary-temp-face
+ "Put target mark.")
+ ("d"
+ dispose
+ nil
+ wl-summary-register-temp-mark
+ wl-summary-exec-action-dispose
+ wl-highlight-summary-disposed-face
+ "Dispose messages according to `wl-dispose-folder-alist'.")
+ ("D"
+ delete
+ nil
+ wl-summary-register-temp-mark
+ wl-summary-exec-action-delete
+ wl-highlight-summary-deleted-face
+ "Delete messages immediately.")
+ ("o"
+ refile
+ wl-summary-get-refile-destination
+ wl-summary-set-action-refile
+ wl-summary-exec-action-refile
+ wl-highlight-summary-refiled-face
+ "Refile messages to the other folder.")
+ ("O"
+ copy
+ wl-summary-get-copy-destination
+ wl-summary-register-temp-mark
+ wl-summary-exec-action-copy
+ wl-highlight-summary-copied-face
+ "Copy messages to the other folder.")
+ ("i"
+ prefetch
+ nil
+ wl-summary-register-temp-mark
+ wl-summary-exec-action-prefetch
+ wl-highlight-summary-prefetch-face
+ "Prefetch messages.")
+ ("~"
+ resend
+ wl-summary-get-resend-address
+ wl-summary-register-temp-mark
+ wl-summary-exec-action-resend
+ wl-highlight-summary-resend-face
+ "Resend messages."))
+ "A variable to define Mark & Action.
+Each element of the list should be a list of
+\(MARK
+ SYMBOL
+ ARGUMENT-FUNCTION
+ SET-MARK-FUNCTION
+ EXEC-FUNCTION
+ FACE
+ DOC-STRING)
+
+MARK is a temporal mark string to define.
+SYMBOL is an action name to define.
+ARGUMENT-FUNCTION is a function called to set the argument data for
+SET-MARK-FUNCTION.
+Its argument is (ACTION NUMBER).
+ACTION is same as the SYMBOL.
+NUMBER is the message number to determine the argument data.
+SET-MARK-FUNCTION is a function called to set the mark.
+Its argument is (NUMBER MARK DATA).
+NUMBER is the target message number.
+MARK is the temporary mark string.
+DATA is given by ARGUMENT-FUNCTION.
+EXEC-FUNCTION is a function called to execute the action.
+Its argument is a list of MARK-INFO.
+MARK-INFO is a list of (NUMBER MARK DATA).
+FACE is a face for highlighting."
+ :type '(repeat (string :tag "Temporary mark")
+ (symbol :tag "Set mark function")
+ (symbol :tag "Unset mark function")
+ (symbol :tag "Exec function")
+ (symbol :tag "Face symbol"))