diff --git a/css/GridFieldExtensions.css b/css/GridFieldExtensions.css
index 5d55657..5c6252c 100644
--- a/css/GridFieldExtensions.css
+++ b/css/GridFieldExtensions.css
@@ -34,12 +34,14 @@
 }
 
 .add-existing-search-dialog .add-existing-search-items li:first-child a {
-	border-radius: 4px 4px 0 0;
+	border-top-left-radius: 4px;
+	border-top-right-radius: 4px;
 	border-top-width: 1px;
 }
 
 .add-existing-search-dialog .add-existing-search-items li:last-child a {
-	border-radius: 0 0 4px 4px;
+	border-bottom-left-radius: 4px;
+	border-bottom-right-radius: 4px;
 }
 
 .add-existing-search-dialog .add-existing-search-items li a:hover {