diff --git a/lisp/org-archive.el b/lisp/org-archive.el
index 2473d7dac..700e59b6b 100644
--- a/lisp/org-archive.el
+++ b/lisp/org-archive.el
@@ -158,7 +158,7 @@ archive file is."
       (save-restriction
 	(goto-char (point-min))
 	(while (re-search-forward
-		"^\\(#\\+\\|[ \t]*:\\)ARCHIVE:[ \t]+\\(.*\\)"
+		"^[ \t]*\\(#\\+\\|:\\)ARCHIVE:[ \t]+\\(.*\\)"
 		nil t)
 	  (setq file (org-extract-archive-file
 		      (org-match-string-no-properties 2)))
diff --git a/lisp/org-element.el b/lisp/org-element.el
index 41df4244a..27e9bdaca 100644
--- a/lisp/org-element.el
+++ b/lisp/org-element.el
@@ -1284,7 +1284,7 @@ CONTENTS is the contents of the element."
 		    (throw 'exit (sort struct 'car-less-than-car))))))
 	    ;; Skip blocks (any type) and drawers contents.
 	    (cond
-	     ((and (looking-at "#\\+BEGIN\\(:\\|_\\S-+\\)")
+	     ((and (looking-at "\\(?:[ \t]*\\)?#\\+BEGIN\\(:\\|_\\S-+\\)")
 		   (re-search-forward
 		    (format "^[ \t]*#\\+END%s[ \t]*$"
 			    (org-match-string-no-properties 1))
diff --git a/lisp/org-list.el b/lisp/org-list.el
index 4b9744f8d..2ac15af15 100644
--- a/lisp/org-list.el
+++ b/lisp/org-list.el
@@ -3044,7 +3044,7 @@ for this list."
     (unless (org-at-item-p) (error "Not at a list item"))
     (save-excursion
       (re-search-backward "#\\+ORGLST" nil t)
-      (unless (looking-at "#\\+ORGLST:[ \t]+SEND[ \t]+\\(\\S-+\\)[ \t]+\\(\\S-+\\)")
+      (unless (looking-at "\\(?:[ \t]\\)?#\\+ORGLST:[ \t]+SEND[ \t]+\\(\\S-+\\)[ \t]+\\(\\S-+\\)")
 	(if maybe (throw 'exit nil)
 	  (error "Don't know how to transform this list"))))
     (let* ((name (match-string 1))
diff --git a/lisp/org-mouse.el b/lisp/org-mouse.el
index 27dc0e070..3d623bf81 100644
--- a/lisp/org-mouse.el
+++ b/lisp/org-mouse.el
@@ -638,7 +638,7 @@ This means, between the beginning of line and the point."
 	    (progn (save-excursion (goto-char (region-beginning)) (insert "[["))
 		   (save-excursion (goto-char (region-end)) (insert "]]")))]
 	   ["Insert Link Here" (org-mouse-yank-link ',event)]))))
-     ((save-excursion (beginning-of-line) (looking-at "#\\+STARTUP: \\(.*\\)"))
+     ((save-excursion (beginning-of-line) (looking-at "[ \t]*#\\+STARTUP: \\(.*\\)"))
       (popup-menu
        `(nil
 	 ,@(org-mouse-list-options-menu (mapcar 'car org-startup-options)
diff --git a/lisp/org.el b/lisp/org.el
index 1ad5e69f7..1863c00ca 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -5938,14 +5938,12 @@ by a #."
 	    (add-text-properties
 	     beg (match-end 0)
 	     '(font-lock-fontified t face font-lock-comment-face)))
-	   ((not (member (char-after beg) '(?\  ?\t)))
-	    ;; just any other in-buffer setting, but not indented
+	   (t ;; just any other in-buffer setting, but not indented
 	    (org-remove-flyspell-overlays-in (match-beginning 0) (match-end 0))
 	    (add-text-properties
 	     beg (match-end 0)
 	     '(font-lock-fontified t face org-meta-line))
-	    t)
-	   (t nil))))))
+	    t))))))
 
 (defun org-fontify-drawers (limit)
   "Fontify drawers."
@@ -9344,7 +9342,7 @@ call CMD."
 	 (goto-char (point-min))
 	 (put-text-property (point) (point-max) 'org-category def-cat)
 	 (while (re-search-forward
-		 "^\\(#\\+CATEGORY:\\|[ \t]*:CATEGORY:\\)\\(.*\\)" nil t)
+		 "^[ \t]*\\(#\\+CATEGORY:\\|[ \t]*:CATEGORY:\\)\\(.*\\)" nil t)
 	   (setq pos (match-end 0)
 		 optionp (equal (char-after (match-beginning 0)) ?#)
 		 cat (org-trim (match-string 2)))
@@ -12137,7 +12135,7 @@ expands them."
 	 (rpl (nth (if musep 2 1) cell))
 	 (ind ""))
     (delete-region start (point))
-    (when (string-match "\\`#\\+" rpl)
+    (when (string-match "\\`[ \t]*#\\+" rpl)
       (cond
        ((bolp))
        ((not (string-match "\\S-" (buffer-substring (point-at-bol) (point))))
@@ -15676,7 +15674,7 @@ formats in the current buffer."
 	  (widen)
 	  (goto-char (point-min))
 	  (while (re-search-forward
-		  "^\\(#\\+COLUMNS:\\|[ \t]*:COLUMNS:\\)[ \t]*\\(.*\\)"
+		  "^[ \t]*\\(#\\+COLUMNS:\\|[ \t]*:COLUMNS:\\)[ \t]*\\(.*\\)"
 		  nil t)
 	    (setq cfmt (match-string 2) s 0)
 	    (while (string-match (org-re "%[0-9]*\\([-[:alnum:]_]+\\)")
@@ -21720,16 +21718,16 @@ and :keyword."
       ;; New the "medium" contexts: clocktables, source blocks
       (cond ((org-in-clocktable-p)
 	     (push (list :clocktable
-			 (and (or (looking-at "#\\+BEGIN: clocktable")
-				  (search-backward "#+BEGIN: clocktable" nil t))
-			      (match-beginning 0))
-			 (and (re-search-forward "#\\+END:?" nil t)
+			 (and (or (looking-at "[ \t]*\\(#\\+BEGIN: clocktable\\)")
+				  (re-search-backward "[ \t]*\\(#+BEGIN: clocktable\\)" nil t))
+			      (match-beginning 1))
+			 (and (re-search-forward "[ \t]*#\\+END:?" nil t)
 			      (match-end 0))) clist))
 	    ((org-in-src-block-p)
 	     (push (list :src-block
-			 (and (or (looking-at "#\\+BEGIN_SRC")
-				  (search-backward "#+BEGIN_SRC" nil t))
-			      (match-beginning 0))
+			 (and (or (looking-at "[ \t]*\\(#\\+BEGIN_SRC\\)")
+				  (re-search-backward "[ \t]*\\(#+BEGIN_SRC\\)" nil t))
+			      (match-beginning 1))
 			 (and (search-forward "#+END_SRC" nil t)
 			      (match-beginning 0))) clist))))
     (goto-char p)