From 30484eccede354c9a4cde12382737939e1bde2c6 Mon Sep 17 00:00:00 2001
From: Richard Heck <rgheck@comcast.net>
Date: Fri, 26 Mar 2010 16:59:08 +0000
Subject: [PATCH] Backport fix for #6454. The real cause may be elsewhere, but
 this does fix the crash and is a worthwhile sanity check in any event.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/branches/BRANCH_1_6_X@33875 a592a061-630c-0410-9148-cb99ea01b6c8
---
 src/TextMetrics.cpp | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/TextMetrics.cpp b/src/TextMetrics.cpp
index 788b5e35b9..f5f9ef5b85 100644
--- a/src/TextMetrics.cpp
+++ b/src/TextMetrics.cpp
@@ -328,13 +328,14 @@ bool TextMetrics::isRTLBoundary(pit_type pit, pos_type pos) const
 bool TextMetrics::isRTLBoundary(pit_type pit, pos_type pos,
 		Font const & font) const
 {
-	if (!lyxrc.rtl_support)
+	if (!lyxrc.rtl_support
+	    // no RTL boundary at paragraph start
+	    || pos == 0
+	    // if the metrics have not been calculated, then we are not
+	    // on screen and can safely ignore issues about boundaries.
+	    || !contains(pit))
 		return false;
 
-	// no RTL boundary at paragraph start
-	if (pos == 0)
-		return false;
-	
 	ParagraphMetrics & pm = par_metrics_[pit];
 	// no RTL boundary in empty paragraph
 	if (pm.rows().empty())