Merge branch 'master' of orgmode.org:org-mode

doc/org.texi

@@ -4770,7 +4770,7 @@ CLOSED       @r{When was this entry closed?}
 TIMESTAMP    @r{The first keyword-less timestamp in the entry.}
 TIMESTAMP_IA @r{The first inactive timestamp in the entry.}
 CLOCKSUM     @r{The sum of CLOCK intervals in the subtree.  @code{org-clock-sum}}
-             @r{must be run first to compute the values.}
+             @r{must be run first to compute the values in the current buffer.}
 BLOCKED      @r{"t" if task is currently blocked by children or siblings}
 ITEM         @r{The content of the entry.}
 FILE         @r{The filename the entry is located in.}

lisp/org.el

@@ -13439,7 +13439,7 @@ a *different* entry, you cannot use these techniques."
 
 (defconst org-special-properties
   '("TODO" "TAGS" "ALLTAGS" "DEADLINE" "SCHEDULED" "CLOCK" "CLOSED" "PRIORITY"
-    "TIMESTAMP" "TIMESTAMP_IA" "BLOCKED" "FILE")
+    "TIMESTAMP" "TIMESTAMP_IA" "BLOCKED" "FILE" "CLOCKSUM")
   "The special properties valid in Org-mode.
 
 These are properties that are not defined in the property drawer,