diff --git a/mozilla/editor/base/nsTextEditor.cpp b/mozilla/editor/base/nsTextEditor.cpp
index b316622284b..16fe3676b1d 100644
--- a/mozilla/editor/base/nsTextEditor.cpp
+++ b/mozilla/editor/base/nsTextEditor.cpp
@@ -1666,6 +1666,9 @@ NS_IMETHODIMP nsTextEditor::OutputTextToStream(nsIOutputStream* aOutputStream, n
       return rv;
   }
 
+  // Try to turn on pretty printing, but don't panic if it doesn't work:
+  (void)encoder->PrettyPrint(PR_TRUE);
+
   return encoder->EncodeToStream(aOutputStream);
 }