diff --git a/app/gateways/gateway_edit.php b/app/gateways/gateway_edit.php
index 76ffb2a52f..83bc031d0f 100644
--- a/app/gateways/gateway_edit.php
+++ b/app/gateways/gateway_edit.php
@@ -529,7 +529,7 @@ if (count($_POST)>0 && strlen($_POST["persistformvar"]) == 0) {
 	echo "		<tr>\n";
 	echo "		<td width=\"30%\" valign=\"top\" class=\"vncell\">".$text['button-advanced-show']."</td>\n";
 	echo "		<td width=\"70%\" class=\"vtable\">\n";
-	echo "			<input type=\"button\" onClick=\"show_advanced_config()\" value=\"".$text['button-advanced']."\"></input></a>\n";
+	echo "			<input type=\"button\" class=\"btn\" onClick=\"show_advanced_config()\" value=\"".$text['button-advanced']."\"></input></a>\n";
 	echo "		</td>\n";
 	echo "		</tr>\n";
 	echo "		</table>\n";