React-Bootstrap v2 Modal container default shifts to document.body creating SSR hydration boundary

Compatibility boundary with React 18 concurrent rendering

React-Bootstrap v2.0.0 changed the default container prop for Modal and Dropdown components to document.body, enabling portal rendering without jQuery. This default creates a hydration mismatch in server-rendered frameworks like Next.js when the portal target exists only on the client. The library currently leaves resolution to user-land container configuration rather than providing a built-in SSR-safe wrapper.

Constraints and uncertainty

• React 18 concurrent mode and strict mode double-invoke effects, potentially exacerbating portal attachment timing.
• Setting container to a client-only element avoids the mismatch but adds boilerplate to every modal instance.
• The rootClose event listener attaches directly to document, which may interact unpredictably with React 18 automatic batching during concurrent renders.

Applications migrating from v1 must decide whether to adopt a global portal wrapper, configure container per instance, or await a potential library-level solution.

1. Does the maintainers' roadmap include an official SSR-safe portal component or a container default that defers to a client-only root?
2. What is the recommended pattern for a shared portal target that works across App Router and Pages Router in Next.js without duplicating container props?
3. Can rootClose behavior be made compatible with React 18 concurrent features without opting out of strict mode?