The main issue is that the renderer (and XAML framework) is struggling with the large amount of pixels due to the very high resolution screen on the Surface Book 3 (and the lack of a powerful GPU). While it's not optimal, if you drop the resolution of the screen, you'll find that MobileSheets will run much more smoothly, as it's not having to render nearly as many pixels. The next update I'm going to release is switching out the graphics framework from Win2D (which uses DirectX) to Skia (which just uses the CPU by default) as users on ARM devices like the Surface Pro X are having all sorts of graphical anomalies with Win2D while annotating.
After the next update is released, please let me know if the performance is any better or worse for you. On my Surface Pro 8, I can scroll smoothly between pages without any jerkiness as you described.
Mike
After the next update is released, please let me know if the performance is any better or worse for you. On my Surface Pro 8, I can scroll smoothly between pages without any jerkiness as you described.
Mike