Why does my .eps file look different from the MATLAB figure on the screen, when I have the 'EraseMode' property of a patch object set to 'xor'?

Why does my .eps file look different from the MATLAB figure on the screen, when I have the 'EraseMode' property of a patch object set to 'xor'?   The .eps file generated from the following code looks different from the figure on the screen:   p1=patch([4 6 6 4],[4 4 6 6],'k'); set(p1,'FaceColor',[0.85 0.85 0.85],'EdgeColor', [1 1 1]); set(p1,'EraseMode','xor'); hold on; plot([1:10],[1:10],'k') print -deps temp I have tried using different renderers. The result is same with all the 3 renderers.