release-notes in .NET 11 Preview 6

[LeafShi1]

PRs merged between 2026-05-19 and 2026-06-22

Release-notes assessment (summary)

Evaluation of whether each PR should be included in the main-branch release notes:

• Recommended for release notes (0): none.
• Not recommended (6):
  • #14606 — although it fixes a regression (DemoConsole app: The SmartTag dialog doesn't disappear when switch the Tabpage items #14600), the bug only reproduces in the internal DemoConsole integration-test harness (src/System.Windows.Forms/tests/IntegrationTests/DesignSurface/DemoConsole), not the real Visual Studio WinForms designer. It is a regression-preview introduced and fixed within the same preview cycle, so no shipped build ever exposed customers to it — no customer-facing impact.
  • #14527 — targets release/10.0 (backport of Fix issue 14458: Clipboard.GetText(TextDataFormat.Rtf) does not retrieve RTF that lacks a null terminating character #14461), not a main change; the fix already reaches main via the original Fix issue 14458: Clipboard.GetText(TextDataFormat.Rtf) does not retrieve RTF that lacks a null terminating character #14461.
  • #14639, #14548, #14596, #14665 — dependency/interop, public-API bookkeeping, and packaging changes with no user-facing behavior change.

Bottom line: No PR in this window warrants a main-branch release note.

Functional fixes

PR	Fixed contents	Description	Comment (release notes?)
#14527	System.Windows.Forms.Clipboard	Backport of #14461 to release/10.0: Clipboard.GetText(TextDataFormat.Rtf) now retrieves RTF that lacks a null-terminating character (external apps like PowerPoint place RTF without a terminator, which is valid per the Windows clipboard spec).	No — targets release/10.0 (backport), not a main PR; main is already covered by the original #14461.
#14606	System.Windows.Forms.ToolStrip (Design / SmartTag)	Fixes the focus issue of SmartTag/DropDown by preserving modal menu tracking of ToolStripDropDown; addresses a regression from #14491 where focus handling was gated too aggressively for ToolStripDropDown/SmartTag-hosted UI.	No — regression (#14600) only reproduces in the internal DemoConsole test harness, not the real WinForms designer; regression-preview introduced and fixed within the same preview cycle, so no customer-facing impact.

Infrastructure / maintenance

Non-automated infrastructure, packaging, and dependency-maintenance PRs (not user-facing bug fixes), sorted by category.

PR	Category	Description	Comment (release notes?)
#14639	Dependency / interop	Updates Microsoft.Windows.CsWin32 0.3.151 → 0.3.287 and removes the manual IComIID .NET Framework workarounds (now emitted by the generator); remaining changes are signature adaptations to keep the solution building.	No — internal dependency/interop maintenance, no user-facing behavior change.
#14548	Public API definitions	Updates PublicAPI.Shipped.txt / PublicAPI.Unshipped.txt for shipped and unshipped items.	No — API-definition bookkeeping only.
#14596	Packaging	Adds PDB and IntelliSense (XML doc) files for the Microsoft.Private.Windows.Core assembly to the NuGet package.	No — packaging/debugging asset change, not a feature or fix.
#14665	Packaging	Updates NuGet packaging version to 6.12.5.	No — packaging version bump.

Notes / Exclusions

Of the 72 PRs merged in this window, the tables above cover functional fixes and non-automated infrastructure/maintenance PRs. Excluded:

• Automated "Source code updates from dotnet/dotnet" (maestro bot, ~50 PRs across main, release/10.0, release/11.0-preview5) — source syncs.
• Automated dependency bumps ("Update dependencies from dotnet/arcade", bot).
• Branding updates — Update branding to 8.0.29 #14602 (8.0.29), Update branding to 9.0.18 #14603 (9.0.18).
• Internal-commit merges — Merging internal commits for release/9.0 #14625 (release/9.0), Merging internal commits for release/8.0 #14626 (release/8.0).
• Test-only PRs — Add tests for PropertyGrid.OnComponentRemoved #14561 (add PropertyGrid tests), Removing unnecessary PropertyGrid tests #14637 (remove unnecessary PropertyGrid tests).