ScriptUI addEventListener broken

Hi,

I am keeping a few old ScriptUI palettes (which have been converted to CEP) as test environment for debugging the extendscript parts. I just noticed that, in Illustrator 24, it was possible to use

button.addEventListener('click', function(ev) { if(ev.shiftKey) ... });

Now, in Illustrator 27, click does no longer call the function.

Here is a workaround

button.onClick = function() {
  var state = ScriptUI.environment.keyboardState;
  if(state.shiftKey) ...  };