--- a/dom/base/nsGlobalWindowCommands.cpp
+++ b/dom/base/nsGlobalWindowCommands.cpp
@@ -561,20 +561,17 @@ nsClipboardCommand::DoCommand(const char
 
   if (notCancelled && !strcmp(aCommandName, "cmd_copyAndCollapseToEnd")) {
     dom::Selection *sel =
       presShell->GetCurrentSelection(SelectionType::eNormal);
     NS_ENSURE_TRUE(sel, NS_ERROR_FAILURE);
     sel->CollapseToEnd();
   }
 
-  if (actionTaken) {
-    return NS_OK;
-  }
-  return NS_ERROR_FAILURE;
+  return actionTaken ? NS_OK : NS_SUCCESS_DOM_NO_OPERATION;
 }
 
 NS_IMETHODIMP
 nsClipboardCommand::GetCommandStateParams(const char *aCommandName,
                                               nsICommandParams *aParams, nsISupports *aCommandContext)
 {
   return NS_ERROR_NOT_IMPLEMENTED;
 }

--- a/dom/html/nsHTMLDocument.cpp
+++ b/dom/html/nsHTMLDocument.cpp
@@ -2882,16 +2882,19 @@ nsHTMLDocument::ExecCommand(const nsAStr
     // which is to look at the focused element, and defer to a focused textbox's controller
     // The code past taken by other commands in ExecCommand always uses the window directly,
     // rather than deferring to the textbox, which is desireable for most editor commands,
     // but not 'cut' and 'copy' (as those should allow copying out of embedded editors).
     // This behaviour is invoked if we call DoCommand directly on the docShell.
     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;
   }
 
   if (commandID.LowerCaseEqualsLiteral("gethtml")) {
     rv.Throw(NS_ERROR_FAILURE);
     return false;