Pardon my burst of bugs, but I'm doing an extensive testing on mobile today. To the chase, when you have a window size set larger than mobile screen resolution, everything scales down just fine, but if you have window of a size that is smaller than the mobile screen resolution, canvas displays screen in a 100% scale not enlarging the window. this also works in preview, in appmobi emulator, so the bug is visible only when installed on mobile (android, nexus one, appmobi export). cheers!