There is no toggle at the moment to forcefully switch from portrait to landscape, as that is not something most users would need or want. It's usually just driven by the rotation sensor unless the user prefers to keep the application in one orientation. As far as the issue you are facing, I think a phone in landscape is problematic for that particular screen because the screen is split into two part, and each part is so small that not all of the content can fit. I will have to change the layout on phones to no longer use this approach and instead just make each section a fixed height with the entire screen being scrollable.
Mike
Mike