(Dialog Boxes): Descibe new optional argument.

diff --git a/lispref/frames.texi b/lispref/frames.texi
index 3b43f18e99db91af99066c0e4c296f8e91170c1c..bb3c827fe34503d21a7e5126dd18bd54eaae1368 100644 (file)
--- a/lispref/frames.texi
+++ b/lispref/frames.texi
@@ -1438,13 +1438,14 @@ the menu keymap as necessary.
 
   A dialog box is a variant of a pop-up menu---it looks a little
 different, it always appears in the center of a frame, and it has just
-one level and one pane.  The main use of dialog boxes is for asking
-questions that the user can answer with ``yes'', ``no'', and a few other
-alternatives.  The functions @code{y-or-n-p} and @code{yes-or-no-p} use
-dialog boxes instead of the keyboard, when called from commands invoked
-by mouse clicks.
-
-@defun x-popup-dialog position contents
+one level and one or more buttons.  The main use of dialog boxes is
+for asking questions that the user can answer with ``yes'', ``no'',
+and a few other alternatives.  With a single button, they can also
+force the user to acknowledge important information.  The functions
+@code{y-or-n-p} and @code{yes-or-no-p} use dialog boxes instead of the
+keyboard, when called from commands invoked by mouse clicks.
+
+@defun x-popup-dialog position contents header
 This function displays a pop-up dialog box and returns an indication of
 what selection the user makes.  The argument @var{contents} specifies
 the alternatives to offer; it has this format:
@@ -1474,6 +1475,10 @@ Dialog boxes always appear in the center of a frame; the argument
 @code{x-popup-menu}, but the precise coordinates or the individual
 window don't matter; only the frame matters.
 
+If @var{header} is non-nil, the frame title for the box is
+``Information'', otherwise it is ``Question''. The former is used
+for @code{message-box} (@pxref{The Echo Area}).
+
 In some configurations, Emacs cannot display a real dialog box; so
 instead it displays the same items in a pop-up menu in the center of the
 frame.