codemirror5: Does not integrate with Chrome's spell check

Code snippet:

<div style="width:200px" contenteditable="true" spellcheck="true">
        <textarea id="code" name="code">
        javaCode {   
            stuff   
        }   
        aaaaaaaaaaaaaa 
        <a>abc</a>;
        </textarea>
    </div>

    <script>
      var editor = CodeMirror.fromTextArea(document.getElementById("code"), 
        {
            lineNumbers: true,
            lineWrapping: true,
            mode: "htmlxml"
        });  
    </script>
    <div contenteditable="true" spellcheck="true">
        pure content editable div. asdf asdf yoh.
    </div>

In Firefox if browser spell check is enabled then inside the editor words are marked. In Chrome, it doesn’t work (maybe not entirely. Sometimes I can trigger one word to be marked but not consistently).

NOTE

I also included a pure content editable div underneath. In Chrome, it won’t mark spelling error at page load time. But once focusing on the word or start editing the content, spell check take into effect. So not sure if is this a Chrome thing or CodeMIrror thing.