a) I'm not sure what are you trying to achieve. If you want to make the Grid 100% and use its scroller, instead of the one on the View, you can use the data-stretch option and then make the Grid 100% high (as the scrolling container doesn't have height on itself). If you had in mind something else, I will need a sample page with the issue isolated.
b) This may be due to the missing devicePixelRatio in Windows Phone which is needed to resize the app to the different device resolutions and sizes. To simulate this, we use a root font-size and since all our Widget styling is based on em units, they are resized accordingly. This may prove a problem for the Grid which is not really meant to fit in a mobile app. Can you share a sample page, reproducing this problem and I will see what I can do to help you fix it? Thank you in advance.
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