diff --git a/dom/base/nsGlobalWindowCommands.cpp b/dom/base/nsGlobalWindowCommands.cpp
index aa54cac83a70..91b0e2d0e000 100644
--- a/dom/base/nsGlobalWindowCommands.cpp
+++ b/dom/base/nsGlobalWindowCommands.cpp
@@ -566,10 +566,7 @@ nsClipboardCommand::DoCommand(const char *aCommandName, nsISupports *aContext)
     sel->CollapseToEnd();
   }
 
-  if (actionTaken) {
-    return NS_OK;
-  }
-  return NS_ERROR_FAILURE;
+  return actionTaken ? NS_OK : NS_SUCCESS_DOM_NO_OPERATION;
 }
 
 NS_IMETHODIMP
diff --git a/dom/html/nsHTMLDocument.cpp b/dom/html/nsHTMLDocument.cpp
index 9fef56f7a7d5..877f0f6672bb 100644
--- a/dom/html/nsHTMLDocument.cpp
+++ b/dom/html/nsHTMLDocument.cpp
@@ -2887,6 +2887,9 @@ nsHTMLDocument::ExecCommand(const nsAString& commandID,
     nsCOMPtr<nsIDocShell> docShell(mDocumentContainer);
     if (docShell) {
       nsresult res = docShell->DoCommand(cmdToDispatch.get());
+      if (res == NS_SUCCESS_DOM_NO_OPERATION) {
+        return false;
+      }
       return NS_SUCCEEDED(res);
     }
     return false;