Disable cmd+enter send in gmail

disable-gmail-cmd-enter.user.js

// ==UserScript==
// @name        Gmail disable cmd+enter
// @namespace   sampdavies@gmail.com
// @description Disables cmd+enter from sending an email in gmail
// @include     ^https?:\/\/mail\.google\.com.*$
// @version     1
// @grant       none
// ==/UserScript==
(function(){
var isMac = unsafeWindow.navigator.oscpu.toLowerCase().contains("mac os x");
unsafeWindow.document.addEventListener('keydown', function(e) {
  // Mac uses the Command key, identified as metaKey
  // Windows and Linux use the Control key, identified as ctrlKey
  var modifier = isMac ? e.metaKey : e.ctrlKey;
  // abort if the proper command/control modifier isn't pressed
  if (!modifier) {
    return;
  }
  
  switch (e.keyCode) {
    case 13: // Enter - (disable cmd-enter to send in gmail)
      e.stopImmediatePropagation();
      return;
  }
  
  // s'more mac love
  if (!isMac) {
      return;
  }
}, true);
})();

This is awesome!

Great idea, I tried today on both Firefox (using Greasemonkey) and Chrome (Tampermonkey) but it does not work for me, Ctrl-Enter still works and the message is sent (anyway I still can stop it with the Undo option).
It's just me?

For me this didn't work anymore.

I created an updated version here:
https://gist.github.com/PatrickvEk/c942b0e2bb0b9f9d34b33820aab07ec5#file-disable-gmail-cmd-enter-2024-user-js

I hope it works for everyone that finds this.