DataMapper: Selecting abstract field choice member causes to skip abstract wrapper

[igarashitm]

Describe the Bug

In FIXML schema, there's "Message" abstract field under choice. Once "Message" is selected, it skips to render the abstract wrapper field as well. Now it's not possible to apply Field Substitution on "Message" abstract field. Abstract field rendering should not be affected by the parent choice selection.

2026-05-08.09-57-30.mp4

Steps to Reproduce the Bug or Issue

1. Attach FIXML schema, choose "FIXML" as a root element - https://www.fixtrading.org/standards/fixml/
2. Apply choice selection: choose "Message" abstract field

Screenshots or Videos

No response

Platform

• OS: [e.g. macOS, Windows, Linux]
• Browser: [e.g. Chrome, Safari, Firefox]
• Version: [e.g. 0.30.0]