--- a/editor/libeditor/html/nsHTMLEditor.cpp
+++ b/editor/libeditor/html/nsHTMLEditor.cpp
@@ -3859,31 +3859,31 @@ nsHTMLEditor::ContentInserted(nsIDocumen
   if (!aChild) {
     return;
   }
 
   if (ShouldReplaceRootElement()) {
     ResetRootElementAndEventTarget();
   }
   // We don't need to handle our own modifications
-  else if (!mAction) {
+  else if (!mAction && (aContainer ? aContainer->IsEditable() : aDocument->IsEditable())) {
     mRules->DocumentModified();
   }
 }
 
 void
 nsHTMLEditor::ContentRemoved(nsIDocument *aDocument, nsIContent* aContainer,
                              nsIContent* aChild, PRInt32 aIndexInContainer,
                              nsIContent* aPreviousSibling)
 {
   if (SameCOMIdentity(aChild, mRootElement)) {
     ResetRootElementAndEventTarget();
   }
   // We don't need to handle our own modifications
-  else if (!mAction) {
+  else if (!mAction && (aContainer ? aContainer->IsEditable() : aDocument->IsEditable())) {
     mRules->DocumentModified();
   }
 }
 
 #ifdef XP_MAC
 #pragma mark -
 #pragma mark  support utils
 #pragma mark -