diff --git a/forms/TreeSelectorField.php b/forms/TreeSelectorField.php
index 7b1fdcba2..75a4161f9 100755
--- a/forms/TreeSelectorField.php
+++ b/forms/TreeSelectorField.php
@@ -13,6 +13,10 @@ class TreeSelectorField extends FormField {
 	}
 	
 	function Field() {
+		Requirements::javascript(THIRDPARTY_DIR . "/prototype.js");
+		Requirements::javascript(THIRDPARTY_DIR . "/behaviour.js");
+		Requirements::javascript(THIRDPARTY_DIR . "/prototype_improvements.js");
+
 		Requirements::add_i18n_javascript(SAPPHIRE_DIR . '/javascript/lang');
 		Requirements::javascript(SAPPHIRE_DIR . "/javascript/TreeSelectorField.js");
 		
@@ -78,4 +82,4 @@ HTML;
 
 }
 
-?>
\ No newline at end of file
+?>