I’ve seen this as well. There is a gamma setting in the Render or Rendering (I can’t recall the exact name) tool panel that can be adjusted to make the two views appear more similar.
Thanks; it’s strange that it’s different/necessary to adjust something in the fist place, isn’t it?
Furthermore: changing the gamma settings affect the model space view, but not the layout.
Turning gamma of in model space creates a shadow similar to the (wrong) one in the layout view, but without the washed out effect in the top of the image: