[Stephen Griffin (stephenegriffin)]

Summary

Fixes #570.

Property copy stopped retaining the raw MAPI source object during the 2021 property-bag refactor, but Paste routing and menu enablement still required that object. This made hierarchy Paste silently do nothing and disabled property-pane Paste.

• Restore an independently owned source-object reference in the shared clipboard cache, preserving existing flags/getter contracts and row-only behavior.
• Keep the source property bag alive across modal dialogs without releasing its borrowed MAPI pointer.
• Use the existing single-property retrieval helper, free the result, and report missing/error-valued results instead of retagging and writing them.
• Add nine permanent native regressions for cache readiness, ownership/lifetime, getter references, row-only sources, and attachment/property clipboard transitions.

Validation

• Debug x64 and x86 builds pass.
• All nine cache regressions pass on both architectures; six failed before the production fix.
• 24 actual-handler x64 PST scenarios pass across hierarchy/base-dialog and property-menu Paste, absent/existing targets, CopyProps and GetProps/SetProps, both cancellation points, missing-source errors, and clipboard replacement during a modal dialog. Assertions include exact values after reopening the target, dialog/commit/SetProps/refresh counts, error notifications, and source-reference balance.
• Four direct provider controls preserve exact binary data after reopening. Two stream probes explicitly return MAPI_E_INTERFACE_NOT_SUPPORTED and leave the target unchanged; they are not counted as successful copies.
• clang-format 17 dry-run and git diff --check pass.
• Temporary diagnostic profiles/PSTs were removed and cleanup verified; no normal profile, mailbox, or Windows clipboard was used.

Live provider/UI validation is limited to an isolated x64 PST. The older 2019 empty-value symptom and Exchange retention-policy behavior were not reproduced and are not claimed fixed. Copy defaults and stream behavior are unchanged.

[github-actions]

Test Results

    8 files  ±  0      8 suites  ±0   56s ⏱️ +4s
  316 tests + 13    316 ✅ + 13  0 💤 ±0  0 ❌ ±0 
2 528 runs  +104  2 528 ✅ +104  0 💤 ±0  0 ❌ ±0 

Results for commit f681b63. ± Comparison against base commit 9f4a0d0.

♻️ This comment has been updated with latest results.