diff --git a/server/index.php b/server/index.php
index 3b43672..2e6305b 100644
--- a/server/index.php
+++ b/server/index.php
@@ -89,7 +89,7 @@ if ($count == 0)
     echo "<b>No user found</b><br/>\n";
 else
 {
-    echo "<b>User</b> <select id=\"selected_user\" name=\"user\" onchange=\"document.getElementById('master_key').value = ''\">" . "\n";
+    echo "<b>User</b> <select id=\"selected_user\" name=\"user\" onchange=\"document.getElementById('master_key').value = '';update_master_key(false);\">" . "\n";
     foreach($users as $u)
     {
         if (is_dir("./users/" . $u) && $u[0] != '_' && $u[0] != '.')