diff --git a/app-proto/src/components/add_remove.rs b/app-proto/src/components/add_remove.rs
index ef5851c..a685482 100644
--- a/app-proto/src/components/add_remove.rs
+++ b/app-proto/src/components/add_remove.rs
@@ -18,6 +18,16 @@ pub fn AddRemove() -> View {
                         // this call is batched to avoid redundant realizations.
                         // it updates the element list and the regulator list,
                         // which are both tracked by the realization effect
+                        /* TO DO */
+                        // it would make more to do the batching inside
+                        // `insert_element_default`, but that will have to wait
+                        // until Sycamore handles nested batches correctly.
+                        //
+                        //   https://github.com/sycamore-rs/sycamore/issues/802
+                        //
+                        // the nested batch issue is relevant here because the
+                        // assembly loaders in the test assembly chooser use
+                        // `insert_element_default` within larger batches
                         state.assembly.insert_element_default::<Sphere>();
                     });
                 }