为什么在网格中以等间距的行/列破坏视图框布局?

Put it simply, I have one Grid with three equally high rows and two buttons. I want to have first button in the first row, then second row empty and finally second button in the third row. This way I get spacing between buttons that is of relative size. I need this rather than hard-coding absolute margin values. So here is the XAML for that:Put it simply, I have one Grid with three equal