A registration under the same key is dropped, as is the row being edited, so the preview
shows the panel that would be saved and not the one it replaces. The result is memoized per
(registration, base list), because the form reads this on every change-detection pass and
compares lists by identity.
basewith the previewed panel added.A registration under the same key is dropped, as is the row being edited, so the preview shows the panel that would be saved and not the one it replaces. The result is memoized per (registration, base list), because the form reads this on every change-detection pass and compares lists by identity.