Thanks for letting me know Angelo - I'm working with both HTML and XPUB export (which will eventually be iOS/Android apps).
We were investigating the idea of creating our own interface but have now decided to use the default app menu - the localisations (to change language), table of content and thumbnails are all very useful.
I have a follow-up question - is it possible to make an action to hide the app menu, or (even better) show/hide the app menu (like the play/pause video action)?
I can make an overlay button to show the app menu, but there is no option to make an action to hide the app menu.
We are concerned about users of our site/app not always knowing to tap to show and hide the app menu and wish to make buttons to help them. We also have pages containing a video that fills the entire page, making it impossible to show/hide the app menu on those pages since any touch plays/pauses the video.