Why the feature app canvas view height is limited to 400px tall while the documentation is listing the infinite height?
Your Yahoo vertical ad is 160x600. The ad is 600 pixel tall leaving 200 pixel in white screen while the app is squeezed into 400 pixel tall with autoflow scroll.
What is the official fold line for app? so developers design the app features above the fold line.
OR consider giving developers flexibility to code. Let us decide height and overflow option. The Small View is already small 300x250. The Canvas View is limited in 760x400 doesn't help to make good app to maximize real estate space. Yahoo Homepage is long enough to scroll below the fold line.
The Canvas view is the application's largest and richest interface for the end user. Usually, the Canvas view is rendered within a Yahoo! landing page, surrounded by a Yahoo! header, footer, and an advertisement unit. End users access a Canvas view from a variety of locations: the Small view, links for user updates, email links, and Web links. Unlike the Small view, the Canvas view supports third-party advertisements and promotions. The size of a Canvas view is 760 px wide with an infinite height.
This feature app is cropped to show the dimenion 760x400