diff --git a/css/GridFieldExtensions.css b/css/GridFieldExtensions.css
index f49c814..f8bd5a8 100644
--- a/css/GridFieldExtensions.css
+++ b/css/GridFieldExtensions.css
@@ -97,7 +97,6 @@
   display: inline-block;
   margin: 0;
   min-width: 150px;
-  width: calc(100% - 20px);
 }
 
 .ss-gridfield-add-new-multi-class .form-group:after {