+(defvar notmuch-show-thread-id nil)
+(make-variable-buffer-local 'notmuch-show-thread-id)
+(put 'notmuch-show-thread-id 'permanent-local t)
+
+(defvar notmuch-show-parent-buffer nil)
+(make-variable-buffer-local 'notmuch-show-parent-buffer)
+(put 'notmuch-show-parent-buffer 'permanent-local t)
+
+(defvar notmuch-show-query-context nil)
+(make-variable-buffer-local 'notmuch-show-query-context)
+(put 'notmuch-show-query-context 'permanent-local t)
+
+(defvar notmuch-show-process-crypto nil)
+(make-variable-buffer-local 'notmuch-show-process-crypto)
+(put 'notmuch-show-process-crypto 'permanent-local t)
+