diff --git a/code/GridFieldAddNewMultiClass.php b/code/GridFieldAddNewMultiClass.php
index dadacef..0b0945a 100755
--- a/code/GridFieldAddNewMultiClass.php
+++ b/code/GridFieldAddNewMultiClass.php
@@ -40,7 +40,7 @@ class GridFieldAddNewMultiClass implements GridField_HTMLProvider, GridField_URL
 	/**
 	 * @var string
 	 */
-	protected $itemRequestClass = 'GridFieldAddNewMultiClassHandler';
+	protected $itemRequestClass = 'SilverStripe\\Forms\\GridField\\GridFieldAddNewMultiClassHandler';
 
 	/**
 	 * @param string $fragment the fragment to render the button in
diff --git a/javascript/GridFieldExtensions.js b/javascript/GridFieldExtensions.js
index 435cdb6..8987740 100644
--- a/javascript/GridFieldExtensions.js
+++ b/javascript/GridFieldExtensions.js
@@ -221,7 +221,7 @@
 				var cls  = this.parents(".ss-gridfield-add-new-multi-class").find("select").val();
 
 				if(cls && cls.length) {
-					this.getGridField().showDetailView(link.replace("{class}", cls));
+					this.getGridField().showDetailView(link.replace("{class}", encodeURI(cls)));
 				}
 
 				return false;