I have called this whole section as "DOM manipulation" (instead of DOM and events), so all the sub-files can be named easily with that context, without prefixing with "element-" or "DOM".
Renamed "DOM manipulation" page title to "Creating elements", then shortended title for "Child and Content" file by removing prefix.
Changes -
1. id - From "element-properties" to "element-child-content". Changed in file and sidebar.js
2. rename file - from "element-properties.mdx" to "element-child-content.mdx"