diff -r dee5afe5301f -r 3f74d0d4af4c src/gui/text/qtextformat.cpp
--- a/src/gui/text/qtextformat.cpp	Mon Mar 15 12:43:09 2010 +0200
+++ b/src/gui/text/qtextformat.cpp	Thu Apr 08 14:19:33 2010 +0300
@@ -3085,7 +3085,8 @@
             f.d = new QTextFormatPrivate;
         f.d->resolveFont(defaultFnt);
 
-        hashes.insert(hash, idx);
+        if (!hashes.contains(hash, idx))
+            hashes.insert(hash, idx);
 
     } QT_CATCH(...) {
         formats.pop_back();