Properly cast two settings to an integer. Props Alexander Concha (@xknown).

Author: Viper007Bond

syntaxhighlighter.php

@@ -4,7 +4,7 @@
 
 Plugin Name:  SyntaxHighlighter Evolved
 Plugin URI:   http://www.viper007bond.com/wordpress-plugins/syntaxhighlighter/
-Version:      3.1.12
+Version:      3.1.13
 Description:  Easily post syntax-highlighted code to your site without having to modify the code at all. Uses Alex Gorbatchev's <a href="http://alexgorbatchev.com/wiki/SyntaxHighlighter">SyntaxHighlighter</a>. <strong>TIP:</strong> Don't use the Visual editor if you don't want your code mangled. TinyMCE will "clean up" your HTML.
 Author:       Alex Mills (Viper007Bond)
 Author URI:   http://www.viper007bond.com/
@@ -21,7 +21,7 @@
 
 class SyntaxHighlighter {
 	// All of these variables are private. Filters are provided for things that can be modified.
-	var $pluginver            = '3.1.12';  // Plugin version
+	var $pluginver            = '3.1.13';  // Plugin version
 	var $agshver              = false;    // Alex Gorbatchev's SyntaxHighlighter version (dynamically set below due to v2 vs v3)
 	var $shfolder             = false;    // Controls what subfolder to load SyntaxHighlighter from (v2 or v3)
 	var $settings             = array();  // Contains the user's settings
@@ -1238,8 +1238,8 @@ function validate_settings( $settings ) {
 				$settings['padlinenumbers'] = (int) $settings['padlinenumbers'];
 
 			$settings['classname']      = ( !empty($settings['classname']) )       ? preg_replace( '/[^ A-Za-z0-9_-]*/', '', $settings['classname'] ) : '';
-			$settings['firstline']      = (int) ( !empty($settings['firstline']) ) ? $settings['firstline'] : $this->defaultsettings['firstline'];
-			$settings['tabsize']        = (int) ( !empty($settings['tabsize']) )   ? $settings['tabsize']   : $this->defaultsettings['tabsize'];
+			$settings['firstline']      = (int) ( ( !empty($settings['firstline']) ) ? $settings['firstline'] : $this->defaultsettings['firstline'] );
+			$settings['tabsize']        = (int) ( ( !empty($settings['tabsize']) )   ? $settings['tabsize']   : $this->defaultsettings['tabsize'] );
 		}
 
 		return $settings;