Is this a right code to disable MathJax right-clicking menu?

Solution 1:

For Mathjax version 3, the information is here: https://docs.mathjax.org/en/latest/options/menu.html

Use this configuration:

<script>
    MathJax = {
        ...
        options: {
            enableMenu: false
            ...
        }
    }
</script>

For version 2 the corresponding setting is documented here: https://docs.mathjax.org/en/v2.7-latest/options/hub.html#configure-hub

and involves the showMathMenu property listed in the question.