Thread:Extension talk:SyntaxHighlighter/Doesn't color code/reply

I had the same problem.

The fix is, to remove the extra one SyntaxHighlighter (boldface in snippet below) while building the $directory variable in 'SyntaxHighlighter.php' in function addHeadItems somewhere about line 137.
 * if( count($this->mSyntaxList) > 0 ) {
 * global $wgScriptPath;
 * $directory = $wgScriptPath.'/extensions/SyntaxHighlighter';
 * $scriptTxt = "\n\r";
 * $scriptTxt = "\n\r";
 * $scriptTxt = "\n\r";