Dating back to the earliest notmuch-pick we have not printed anything
for the tag field for a message with no tags. This is inconsistent
with search and show both of which print "()". Change pick to be
consistent.
            (face (if match
                          'notmuch-pick-match-tag-face
                        'notmuch-pick-no-match-tag-face)))
-       (when tags
-         (insert (propertize (format format-string
-                                     (mapconcat #'identity tags ", "))
-                             'face face))))))))
+       (insert (propertize (format format-string
+                                   (mapconcat #'identity tags ", "))
+                           'face face)))))))
 
 (defun notmuch-pick-insert-msg (msg)
   "Insert the message MSG according to notmuch-pick-result-format"