diff --git a/mozilla/layout/base/nsBidiPresUtils.cpp b/mozilla/layout/base/nsBidiPresUtils.cpp
index c5f7138e324..8e404960dfb 100644
--- a/mozilla/layout/base/nsBidiPresUtils.cpp
+++ b/mozilla/layout/base/nsBidiPresUtils.cpp
@@ -341,6 +341,7 @@ nsBidiPresUtils::Resolve(nsPresContext* aPresContext,
                                    frameIndex, newIndex, temp);
             aForceReflow = PR_TRUE;
             runLength -= temp;
+            fragmentLength -= temp;
             lineOffset += temp;
             frameIndex = newIndex;
           }