tinymce-docs-4x/_includes/configuration/allow-conditional-comments.md

allow_conditional_comments

This option allows you to specify whether the editor should parse and keep conditional comments.

Type: Boolean

Default Value: true // confirmation required

Possible Values: true, false

Example:

tinymce.init({
  selector: "textarea",  // change this value according to your html
  allow_conditional_comments: false
});