Missing lines when shading cells

Question

I cannot figure out why lines are not being showed on the shaded columns. Can I get a little help finding what is wrong?

EDIT: The MWE follows:

\documentclass[12pt, a4paper]{article}
\usepackage[english]{babel}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage {setspace} \doublespacing 
\usepackage{fullpage}
\usepackage{graphicx, pdflscape}
\usepackage{tikz}
\usepackage{colortbl}    %for shading*
\usepackage{pifont}    %for pointing hand
\usepackage{arydshln}    %for dashed lines
\begin{document}

\begin{center} \renewcommand*\arraystretch{1.2}
\scalebox{1}[1]{\begin{tabular}[t]{|rrl||c|c|c|} \hline 
\multicolumn{3}{|c||}{kesaks} & CF & CS & F \\[0.5ex]
\hline \hline a. & \ding{43} & kesaks & $\ast$$\ast$ & \cellcolor{lightgray} & \cellcolor{lightgray} \\
\hline b. & & gesaks & $\ast$$\ast$$\ast$! & \cellcolor{lightgray}$\ast$ & \cellcolor{lightgray}$\ast$ \\
\hline c. & & gezaks & $\ast$$\ast$$\ast$!$\ast$ & \cellcolor{lightgray}$\ast$$\ast$ & \cellcolor{lightgray}$\ast$$\ast$ \\
\hline d. & & gezags & $\ast$$\ast$$\ast$!$\ast$$\ast$ & \cellcolor{lightgray}$\ast$$\ast$ & \cellcolor{lightgray}$\ast$$\ast$$\ast$ \\
\hline  e. & & gezagz & $\ast$$\ast$$\ast$!$\ast$$\ast$$\ast$ & \cellcolor{lightgray} & \cellcolor{lightgray}$\ast$$\ast$$\ast$$\ast$$\ast$ \\
\hline \end{tabular}} \renewcommand*\arraystretch{1} \end{center}

\end{document}