title: What is d:IsOptimized in Expressions Blend?
body: <p>Just out of curiously, what is d:IsOptimized in Expressions Blend?</p>
  
  <p>While I know that d: is a namespace for design-time attributes, does anyone know what d:IsOptimized actually does?  Is there anywhere that these Blend-specific attributes are documented?</p>
  
  <p>It's not in the design-time attributes supported (and documented) by Visual Studio:
  <a href="http://msdn.microsoft.com/en-us/library/ff602277(VS.95).aspx" rel="nofollow noreferrer">http://msdn.microsoft.com/en-us/library/ff602277(VS.95).aspx</a></p>
  
  <p>Any ideas?</p>