diff --git a/mozilla/editor/base/nsHTMLEditor.cpp b/mozilla/editor/base/nsHTMLEditor.cpp
index 2012a09a449..60132e29a9e 100644
--- a/mozilla/editor/base/nsHTMLEditor.cpp
+++ b/mozilla/editor/base/nsHTMLEditor.cpp
@@ -3377,6 +3377,8 @@ NS_IMETHODIMP nsHTMLEditor::OutputToString(nsString& aOutputString,
         aOutputString = "";
         return NS_OK;
       }
+      else if (mFlags & eEditorPlaintextMask)
+        aFlags |= nsIDocumentEncoder::OutputPreformatted;
     }
 
     nsCOMPtr<nsIDocumentEncoder> encoder;
diff --git a/mozilla/editor/libeditor/html/nsHTMLEditor.cpp b/mozilla/editor/libeditor/html/nsHTMLEditor.cpp
index 2012a09a449..60132e29a9e 100644
--- a/mozilla/editor/libeditor/html/nsHTMLEditor.cpp
+++ b/mozilla/editor/libeditor/html/nsHTMLEditor.cpp
@@ -3377,6 +3377,8 @@ NS_IMETHODIMP nsHTMLEditor::OutputToString(nsString& aOutputString,
         aOutputString = "";
         return NS_OK;
       }
+      else if (mFlags & eEditorPlaintextMask)
+        aFlags |= nsIDocumentEncoder::OutputPreformatted;
     }
 
     nsCOMPtr<nsIDocumentEncoder> encoder;