Make `C-u C-x =' be more verbose about invisible characters

* lisp/descr-text.el (describe-text-properties-1): Note confusing
bits about invisible characters (bug#3400).

1 files changed, 4 insertions, 0 deletions

diff --git a/lisp/descr-text.el b/lisp/descr-text.el
index a8160889325..0f01ad676ae 100644
--- a/lisp/descr-text.el
+++ b/lisp/descr-text.el
@@ -176,6 +176,10 @@ otherwise."
         (insert "\n"))
       ;; Text properties
       (when properties
+        (when (plist-get properties 'invisible)
+          (insert "\nNote that character has an invisibility property,\n"
+                  "  so the character displayed at point in the buffer may\n"
+                  "  differ from the character described here.\n"))
         (newline)
         (insert "There are text properties here:\n")
         (describe-property-list properties)))))