Remove padding/borders between Grid cell rows & columns

I am trying to remove the cell padding/borders in a Grid. I have read this thread: https://forums.xamarin.com/discussion/23295/can-the-padding-between-rows-in-a-grid-be-changed but none of the methods discussed there allow me to remove the spaces. How do I remove the invisible cell borders?

I've tried :

<Grid.RowDefinitions RowSpacing="0" 
<Grid.ColumnDefinitions ColumnSpacing="0" 

And obviously I've tried Padding="0" in the <Grid and <Grid.RowDefinitions and <Grid.ColumnDefinitions, but no luck.