Anyone have idea idea why this happens: I make a second line symbol layer under the first, a white underlay so the blue line will have a halo. Blue line is 1pt, white line is 4pt. It draws but instead of white it just wipes out all the vector layers below it and shows just the raster layer underneath, as Illustrated below. If I change the white to red it shows up properly. Why on earth is this happening?
Do you maybe have a blending mode applied?
Nope. I just reset my machine and now it works. May be everyone's favorite kind of bug, one that can't be duplicated.