Doc fix for make-text-button.

* doc/lispref/display.texi (Making Buttons): Mention limitation of text buttons.

* lisp/button.el (make-text-button): Doc fix.  (See bug#7881)

4 files changed, 22 insertions, 15 deletions

diff --git a/doc/lispref/ChangeLog b/doc/lispref/ChangeLog
index e1180124c05..f81a3069f80 100644
--- a/doc/lispref/ChangeLog
+++ b/doc/lispref/ChangeLog
@@ -1,3 +1,7 @@
+2011-01-22  Glenn Morris  <rgm@gnu.org>
+
+	* display.texi (Making Buttons): Mention limitation of text buttons.
+
 2011-01-08  Chong Yidong  <cyd@stupidchicken.com>
 
 	* files.texi (Directory Names): Move directory-abbrev-alist doc to
@@ -8681,5 +8685,3 @@
 
   You should have received a copy of the GNU General Public License
   along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
-
-;;; arch-tag: 985ae0ce-df29-475b-b3f8-4bbcbf6f7fda
diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
index 7caa3571aeb..0a9fa30c599 100644
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@@ -4962,8 +4962,9 @@ and returns it.
 button actually part of the text instead of being a property of the
 buffer.  Buttons using text properties do not create markers into the
 buffer, which is important for speed when you use extremely large
-numbers of buttons.  Both functions return the position of the start
-of the new button:
+numbers of buttons.  (However, if there is an existing face text
+property at the site of the button, the button face may not be visible.)
+Both functions return the position of the start of the new button:
 
 @defun make-text-button beg end &rest properties
 This makes a button from @var{beg} to @var{end} in the current buffer, using
@@ -5904,7 +5905,3 @@ This hook is used for internal purposes: setting up communication with
 the window system, and creating the initial window.  Users should not
 interfere with it.
 @end defvar
-
-@ignore
-   arch-tag: ffdf5714-7ecf-415b-9023-fbc6b409c2c6
-@end ignore
diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 9f0d1f0d096..b07de89a460 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,7 @@
+2011-01-22  Glenn Morris  <rgm@gnu.org>
+
+	* button.el (make-text-button): Doc fix.  (See bug#7881)
+
 2011-01-22  Chong Yidong  <cyd@stupidchicken.com>
 
 	* simple.el (line-move-visual): Doc fix (Bug#7594).
diff --git a/lisp/button.el b/lisp/button.el
index ef7161213fd..4881d9f8741 100644
--- a/lisp/button.el
+++ b/lisp/button.el
@@ -1,7 +1,7 @@
 ;;; button.el --- clickable buttons
 ;;
-;; Copyright (C) 2001, 2002, 2003, 2004, 2005,
-;;   2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
+;; Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
+;;   2010, 2011  Free Software Foundation, Inc.
 ;;
 ;; Author: Miles Bader <miles@gnu.org>
 ;; Keywords: extensions
@@ -37,7 +37,9 @@
 ;; the button is represented by a marker or buffer-position pointing
 ;; somewhere in the button.  In the latter case, no markers into the
 ;; buffer are retained, which is important for speed if there are are
-;; extremely large numbers of buttons.
+;; extremely large numbers of buttons.  Note however that if there is
+;; an existing face text-property at the site of the button, the
+;; button face may not be visible.  Using overlays avoids this.
 ;;
 ;; Using `define-button-type' to define default properties for buttons
 ;; is not necessary, but it is is encouraged, since doing so makes the
@@ -289,9 +291,12 @@ button-type from which to inherit other properties; see
 `define-button-type'.
 
 This function is like `make-button', except that the button is actually
-part of the text instead of being a property of the buffer.  Creating
-large numbers of buttons can also be somewhat faster using
-`make-text-button'.
+part of the text instead of being a property of the buffer.  That is,
+this function uses text properties, the other uses overlays.
+Creating large numbers of buttons can also be somewhat faster
+using `make-text-button'.  Note, however, that if there is an existing
+face property at the site of the button, the button face may not be visible.
+You may want to use `make-button' in that case.
 
 BEG can also be a string, in which case it is made into a button.
 
@@ -476,5 +481,4 @@ Returns the button found."
 
 (provide 'button)
 
-;; arch-tag: 5f2c7627-413b-4097-b282-630f89d9c5e9
 ;;; button.el ends here