fix css on datetime widget

Resources/public/css/layout.css

@@ -251,6 +251,10 @@
     height: 125px;
 }
 
+.sonata-bc div.sonata-medium-date {
+    overflow: hidden;
+}
+
 .sonata-bc div.sonata-medium-date select {
     width: 75px;
 }