Portrait page vertically scrollable

In the emulator, the page is viewed entirely using single\dual mode

Check the screenshot.

Yes indeed, I as viewing it in vertical scroll in sample app. So there is a difference in version then?

The vertical mode fits according to screen width, so it's normal to see it this way.

What version you are using? Cannot you update the version you are using?

Or at least try to check the difference in Dual view between your version and the demo's version.

Isn't the PDFViewDual contained in jar? I only have class files. It's hard to change that code.
Updating to a newer version is a bit of work too, because I did changed some things in the code.