[Stephen Griffin (stephenegriffin)]

Summary

Fix embedded-message recipient/attachment table commands and double-click when View embedded message properties is enabled for an MSG file.

The property pane already holds the embedded IMessage. Opening it again fails with access denied in the MSG provider, so the existing handlers produce no window. Reuse the displayed message when the requested attachment matches the current cached attachment, using the existing QueryInterface helper to return an owned reference. Leave normal open/fallback behavior unchanged when no matching displayed message exists.

Fixes #778.

Validation

• Reproduced on the current-main x64 baseline with synthetic Unicode MSGs of classes IPM.Note and IPM.Appointment: four missing table windows and two failed inline double-clicks. Releasing the property pane restores access, confirming the reopen/lifetime interaction.
• All 16 post-fix actual-UI table checks pass, verifying the embedded message's recipient and attachment data rather than only window existence or row counts. Both inline double-click failures recover; separate-message and released-pane controls remain working.
• Debug Unicode x64 and x86 builds pass; clang-format 17 and git diff --check pass.
• Runtime checks are x64 only: x86 MAPIInitialize fails because this environment lacks a working 32-bit provider.
• Fixtures are synthetic, not a real recurring-meeting exception. UI checks are session-only integration diagnostics, not additional permanent UnitTest coverage.
• No profile logon, mailbox access, registry writes, or unrelated user data. Disposable fixtures and diagnostic binaries were cleaned up.

[github-actions]

Test Results

    8 files  ±0      8 suites  ±0   38s ⏱️ -14s
  288 tests ±0    288 ✅ ±0  0 💤 ±0  0 ❌ ±0 
2 304 runs  ±0  2 304 ✅ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit c0a8f1f. ± Comparison against base commit 8f0bac3.

♻️ This comment has been updated with latest results.