diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index 057d3e5f301..805b64e36e2 100644
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -6040,6 +6040,27 @@ function check_php_version($version='4.1.0') {
     return (version_compare(phpversion(), $version) >= 0);
 }
 
+/**
+ * Checks to see if is the browser operating system matches the specified 
+ * brand.
+ * 
+ * Known brand: 'Windows','Linux','Macintosh','SGI','SunOS','HP-UX'
+ *
+ * @uses $_SERVER
+ * @param string $brand The operating system identifier being tested 
+ * @return bool true if the given brand below to the detected operating system
+ */
+ function check_browser_operating_system($brand) {
+    if (empty($_SERVER['HTTP_USER_AGENT'])) {
+        return false;
+    }
+
+    if (preg_match("/$brand/i", $_SERVER['HTTP_USER_AGENT'])) {
+        return true;
+    }
+     
+    return false;  
+ }
 
 /**
  * Checks to see if is a browser matches the specified
diff --git a/lib/weblib.php b/lib/weblib.php
index 425f59b980c..ad1b768aa93 100644
--- a/lib/weblib.php
+++ b/lib/weblib.php
@@ -1178,7 +1178,9 @@ $targetwindow='self', $selectlabel='', $optionsextra=NULL) {
 
     //IE and Opera fire the onchange when ever you move into a dropdwown list with the keyboard. 
     //onfocus will call a function inside dropdown.js. It fixes this IE/Opera behavior.
-    if (check_browser_version('MSIE') || check_browser_version('Opera')) {
+    //Note: There is a bug on Opera+Linux with the javascript code (first mouse selection is inactive), 
+    //so we do not fix the Opera behavior on Linux
+    if (check_browser_version('MSIE') || (check_browser_version('Opera') && !check_browser_operating_system("Linux"))) {
         $output .= '<div>'.$selectlabel.$button.'<select id="'.$formid.'_jump" onfocus="initSelect(\''.$formid.'\','.$targetwindow.')" name="jump">'."\n";
     }
     //Other browser