+ (condition-case err
+ (funcall notmuch-show-mark-read-function (window-start) (window-end))
+ ((debug error)
+ (unless notmuch-show--seen-has-errored
+ (setq notmuch-show--seen-has-errored 't)
+ (setq header-line-format
+ (concat header-line-format
+ (propertize " [some mark read tag changes may have failed]"
+ 'face font-lock-warning-face)))))))))