This will take more work than the simpler functions. For this, we need to:

• Wire wikitext model into booklet helper as a read-only data source. This will be read to find the current template parameter items and remove them. Perhaps in the future this dependency can be dropped in favor of fully encapsulating each template, so we just remove a template-level container.
• Take over all item removal responsibilities.
• Take over UI wiring and unwiring.
• May need to migrate the "reselect" feature, this currently depends on low-level integration with add/remove operations. Document current reselect behavior. Try to leave that behavior unchanged.