Added more visible border to placeholder when row has active-child

src/Umbraco.Web.UI.Client/src/less/components/umb-grid.less

@@ -404,6 +404,14 @@
     .umb-grid-has-config {
         color: fade(@black, 44);
     }
+
+    .umb-cell-content.-placeholder {
+        border-color: @grayLight;
+
+        &:hover {
+            border-color: fade(@gray, 44);
+        }
+    }
 }