InAppBrowser unable to handle nested content?

I have some help docs that I want to render in the InAppBrowser. They are a series of nested HTML, JS and CSS files; when I point to the top level .htm file, the IAB comes up blank since there is nothing in the body; it is used to load other HTML files. However, when I point to a file deeper in the nest, say Home.htm, I can see that page's content, but none of the dynamic content works: the hamburger menu doesn't function, navigation to other pages does not work, etc. The site was built using MadCap Flare; here is one of their example projects that exhibits the same symptoms: https://github.com/skrawn/madcap_example Any ideas about what could cause it?

Start by reproducing the blank top-level .htm and nonfunctional Home.htm behavior in the InAppBrowser using the linked MadCap Flare example project. Inspect how its nested HTML, JS, and CSS files are loaded and how navigation is handled. Done means the nested help site renders and its dynamic menu and page navigation work when opened through the plugin.

Written by the indexing model from the issue text.