[j-n-m]

Tapping to turn a page works in portrait mode. In landscape mode, a tap brings up the pop-up & the bar that I see when e.g. I am going to add a smart button; it also brings up the page-turn slider, which works.
This is not a big issue for me, as I will be playing always using portrait mode.  It's just an irritation when I'm entering new sheets, say.
(HP x360 Omnibook)

[Zubersoft]

It depends where on the screen you are tapping. You need to tap on the left 25% or so of the screen to turn back a page, and right 25% or so of the screen to turn forward a page. This is still true in landscape. It's not the page you need to tap on - it's the edge of the tablet screen itself.

Mike

[j-n-m]

Thanks, Mike.  Yes, tapping by the screen edge rather than on the sheet does turn the page.