[listings] correct caption

my-listings.sty

@@ -182,15 +182,10 @@
 \RequirePackage{xcolor}
 \RequirePackage{caption}
 
-\DeclareCaptionFont{white}{\color{black}}
-\DeclareCaptionFormat{listing}{%
-  \colorbox{gray}{%
-    \noindent\parbox{\dimexpr\columnwidth-2\fboxsep}{#1#2#3}%
-  }%
-}
-\captionsetup[lstlisting]{format=listing, labelfont=white, textfont=white,
-  singlelinecheck=false, margin=0pt, font={bf}}
+\DeclareCaptionFont{white}{\color{white}}
 
+\captionsetup[lstlisting]{box=colorbox, boxcolor=gray, labelfont=white,
+  textfont=white, singlelinecheck=false, margin=0pt, font={bf}}
 \colorlet{isae@bggray}{gray!20}
 
 % styles