title: WPF Margins are large numbers. Don't appear to be relative to other controls, just borders
body: <p>When I define the margin width of my rectangle objects in WPF, they snap to the edge of the page, i.e. Margin="10,10,0,0" puts it in the top left corner instead of snapping to a 10,10 border around other objects. When I drag it to the correct place I want it to be, the margins end up with numbers like this: Margin="684,810,0,0"</p>
  
  <p>It seems like the numbers are being set relative to the edges of my form, how can I fix this?</p>