some lines appear thick, others do not [closed]

using the following code only makes the lines surrounding the rectangle specified in the last 'draw' command line, the rest appear normal regardless of the attempt at making them thick

 \usepackage{tikz}
\begin{document}

\begin{tikzpicture}
\draw[draw=gray, dashed, thick, ->] (4.125,-4) -- (4.125,4);
\draw[dashed, very thick, ->] (0,0) -- (8,0);
\filldraw[thick , fill=gray, draw=black] (4,1) rectangle (4.25,3);
\filldraw[thick , fill=gray, draw=black] (4,-0.5) rectangle (4.25,0.5);
\filldraw[thick , fill=gray, draw=black] (4,-1) rectangle (4.25,-3);
\filldraw[thick , fill=red, draw=black] (0,0.75) circle (0.1cm);
\filldraw[thick , fill=blue, draw=black] (0,-0.75) circle (0.1cm);
\draw[thick , ->] (0.1,0.75) -- (4.25,0.75);
\draw[thick , ->] (0.1,-0.75) -- (4.25, -0.75);
\filldraw[thick, draw=black, fill=gray] (8,-3) rectangle (8.25,3);

\end{tikzpicture}
\end{document}


closed as off-topic by cfr, Mensch, barbara beeton, Robert, TroyNov 17 '17 at 5:02

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• It seems to be a viewer issue. Try different viewers and/or zoom in. With a high enough zoom you'll very likely see, that the line widths are correct. – Mike Nov 17 '17 at 0:20
• I'm voting to close this question as off-topic because resolved in comments (viewer issue). – cfr Nov 17 '17 at 2:51