diff -uNr qt-everywhere-opensource-src-4.6.1.orig/src/gui/text/qtextcursor.cpp qt-everywhere-opensource-src-4.6.1/src/gui/text/qtextcursor.cpp
--- qt-everywhere-opensource-src-4.6.1.orig/src/gui/text/qtextcursor.cpp	2010-01-16 00:01:34.000000000 +0700
+++ qt-everywhere-opensource-src-4.6.1/src/gui/text/qtextcursor.cpp	2010-02-23 08:44:10.767987332 +0700
@@ -503,8 +503,10 @@
             while (relativePos < len && engine->atWordSeparator(relativePos))
                 ++relativePos;
         } else {
-            while (relativePos < len && !engine->atSpace(relativePos) && !engine->atWordSeparator(relativePos))
+            while (relativePos < len && !engine->atSpace(relativePos) && !engine->atWordSeparator(relativePos)) {
                 ++relativePos;
+                if (engine->attributes() && engine->attributes()[relativePos].wordBoundary) break;
+            }
         }
         newPosition = blockIt.position() + relativePos;
         break;
diff -uNr qt-everywhere-opensource-src-4.6.1.orig/src/gui/text/qtextengine.cpp qt-everywhere-opensource-src-4.6.1/src/gui/text/qtextengine.cpp
--- qt-everywhere-opensource-src-4.6.1.orig/src/gui/text/qtextengine.cpp	2010-01-16 00:01:34.000000000 +0700
+++ qt-everywhere-opensource-src-4.6.1/src/gui/text/qtextengine.cpp	2010-02-23 08:52:13.576747529 +0700
@@ -1650,6 +1650,9 @@
                 }
             }
 
+            if (logClusters[pos + ilen - 1] >= glyphs.numGlyphs)
+                logClusters[pos + ilen - 1] = glyphs.numGlyphs - 1;
+
             glyph_t glyph = glyphs.glyphs[logClusters[pos + ilen - 1]];
             glyph_metrics_t gi = fe->boundingBox(glyph);
             if (gi.isValid())
diff -uNr qt-everywhere-opensource-src-4.6.1.orig/src/gui/text/qtextlayout.cpp qt-everywhere-opensource-src-4.6.1/src/gui/text/qtextlayout.cpp
--- qt-everywhere-opensource-src-4.6.1.orig/src/gui/text/qtextlayout.cpp	2010-01-16 00:01:34.000000000 +0700
+++ qt-everywhere-opensource-src-4.6.1/src/gui/text/qtextlayout.cpp	2010-02-23 08:51:08.708737389 +0700
@@ -658,6 +658,8 @@
 
     if (oldPos >= len)
         return oldPos;
+
+    int checkPos = oldPos;
     if (mode == SkipCharacters) {
         oldPos++;
         while (oldPos < len && !attributes[oldPos].charStop)
@@ -668,8 +670,11 @@
             while (oldPos < len && d->atWordSeparator(oldPos))
                 oldPos++;
         } else {
-            while (oldPos < len && !d->atSpace(oldPos) && !d->atWordSeparator(oldPos))
+            while (oldPos < len && !d->atSpace(oldPos) && !d->atWordSeparator(oldPos)) {
+                if (checkPos != oldPos && attributes[oldPos].wordBoundary)
+                    break;
                 oldPos++;
+            }
         }
         while (oldPos < len && d->atSpace(oldPos))
             oldPos++;
@@ -703,8 +708,11 @@
             while (oldPos && d->atWordSeparator(oldPos-1))
                 oldPos--;
         } else {
-            while (oldPos && !d->atSpace(oldPos-1) && !d->atWordSeparator(oldPos-1))
+            while (oldPos && !d->atSpace(oldPos-1) && !d->atWordSeparator(oldPos-1)) {
                 oldPos--;
+                if (attributes[oldPos].wordBoundary)
+                    break;
+            }
         }
     }
 //     qDebug("  -> %d", oldPos);
@@ -2018,7 +2026,7 @@
             x += w;
         if (ul && *ul != -1 && *ul < end) {
             // draw underline
-            gtmp = (*ul == end-1) ? ge : logClusters[*ul+1-si.position];
+            gtmp = (*ul == end-1) ? ge : logClusters[*ul-si.position]+1;
             ++stmp;
             gf.glyphs = glyphs.mid(gs, gtmp - gs);
             gf.num_chars = stmp - start;