wrong colors thin lines

[chloros]

Dear Octave users,

i've attached the image of a meshplot and some line diagrams as they
appear on my laptop (intel graphics). If the line width is set to 2 or
greater, everything is fine. For the standard line width and line width
1, the colors are somehow twisted.

It happens with 4.2.2 (comes pre-installed with Fedora Core 27) and the
behavior is the same with a build made from the last mercurial
development branch.

I really do not know what else I could do. If anyone has an idea, please let me 
know.

figure;
plot([0 1],[0.5 0.5],'color',[0 0 1])
hold on
plot([0 1],[1 1],'color',[0 0 1],'LineWidth',1)
plot([0 1],[2 2],'color',[0 0 1],'LineWidth',2)
plot([0 1],[3 3],'color',[0 0 1],'LineWidth',3)
ylim([0 4]);

figure;
[X,Y,Z]=sombrero;
mesh(X,Y,Z,Z);

Best regards
Chloros

screenshot.png
Description: PNG image