I am trying to insert text without it entering the undo buffer. Essentially, sometimes I do not want inserted text to be able to be removed by undoing. To do this, I have tried, tinymce.UndoManager.transact and tinymce.UndoManager.ignore, but neither seem to result in the desired behavior. Example insert code:

editor.undoManager.transact(function () {
   editor.execCommand('mceInsertContent', false, '<span>My value here</span>');
});

I do not want the inserted span above to be affected by undo, but it is. How do I achieve this?