diff --git a/lisp/org.el b/lisp/org.el
index 3eb79fbf8..a5a32c936 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -13465,7 +13465,7 @@ With prefix ARG, realign all tags in headings in the current buffer."
 		     current-tags inherited-tags table
 		     (if org-fast-tag-selection-include-todo
 			 org-todo-key-alist))
-		  (let ((org-add-colon-after-tag-completion t))
+		  (let ((org-add-colon-after-tag-completion (< 1 (length table))))
 		    (org-trim
 		     (org-icompleting-read "Tags: "
 					   'org-tags-completion-function
@@ -13749,9 +13749,10 @@ Returns the new tags string, or nil to not change the current settings."
 		  (condition-case nil
 		      (setq tg (org-icompleting-read
 				"Tag: "
-				(or buffer-tags
-				    (with-current-buffer buf
-				      (org-get-buffer-tags)))))
+				(append (or buffer-tags
+					    (with-current-buffer buf
+					      (org-get-buffer-tags)))
+					(mapcar 'car table))))
 		    (quit (setq tg "")))
 		  (when (string-match "\\S-" tg)
 		    (add-to-list 'buffer-tags (list tg))