(define-key map (kbd "RET") 'notmuch-search-show-thread)
(define-key map (kbd "M-RET") 'notmuch-tree-from-search-thread)
(define-key map "Z" 'notmuch-tree-from-search-current-query)
(define-key map (kbd "RET") 'notmuch-search-show-thread)
(define-key map (kbd "M-RET") 'notmuch-tree-from-search-thread)
(define-key map "Z" 'notmuch-tree-from-search-current-query)