I am also experiencing this problem working in SketchUp/Layout 2014. I have tried changing the OpenGL setting and it has not solved the issue. I am on a Mac, so I can't update my GPU driver short of upgrading my operating system.
One thing I noticed is that I seem to consistently experience this problem when working in files that I originally created in SketchUp 2013 (last year). I have not seen this happen with files originally created in SketchUp 2014 imported into Layout 2014.
Here are two example screenshots of the problem. In the first view, the rendering mode in Layout is set to "vector." In the second, it is set to "raster." I did not change anything else.
Thanks for any advice anyone can provide!
COROVector_07.jpg
CORORaster_07.jpg