fix: prevent custom event and tooltip errors

[James Newton-King (JamesNK)]

Pull Request

📖 Description

Removes the need for the application-level startup workaround used with Fluent UI Blazor 5.0.0-rc.5:

• Registers each Fluent custom event once through the existing global registration state, preventing duplicate registration when Blazor Web and Server startup hooks both run.
• Maps the Blazor overflowchange custom event to a distinct internal fluentoverflowchange browser event, as required by .NET 11.
• Continues dispatching the public overflowchange DOM event for JavaScript consumers.
• Overrides showPopover() only for fluent-tooltip so a delayed tooltip callback is ignored after the element has been disconnected. This avoids Chromium's invalid-state exception without modifying HTMLElement.prototype globally.

The failures were found while running Fluent UI Blazor with Native AOT on .NET 11 in microsoft/aspire#19565.

🎫 Issues

Related to #4626.

👩‍💻 Reviewer Notes

Please focus on the dual overflow event dispatch and the global defineOnce registration key. The public Blazor event remains overflowchange, and the documented DOM event remains available; fluentoverflowchange is an internal bridge event.

The tooltip override intentionally delegates to the original fluent-tooltip showPopover implementation only while the tooltip remains connected.

📑 Test Plan

• npm run build
• node ./esbuild.config.mjs --build-mode=Release
• git diff --check
• Confirmed no TypeScript diagnostics in the changed files.

✅ Checklist

General

• I have added tests for my changes.
• I have tested my changes.
• I have updated the project documentation to reflect my changes.
• I have read the CONTRIBUTING documentation and followed the standards for this project.

Component-specific

• I have added a new component
• I have added Unit Tests for my new component
• I have modified an existing component
• I have validated the Unit Tests for an existing component

⏭ Next Steps

No follow-up work is currently required.

[James Newton-King (JamesNK)]

Javier Calvarro Nelson (@javiercn) This was found while running Fluent UI Blazor v5 with Native AOT on .NET 11 in microsoft/aspire#19565.

[James Newton-King (JamesNK)]

Please manual test before merging. I've just made suggested changes by AI, I haven't done any manual testing.

[Copilot]

Pull request overview

This PR updates the Core.Scripts startup/runtime wiring to avoid .NET 11 Blazor custom-event registration failures and to prevent tooltip popover callbacks from throwing after the element is removed from the DOM.

Changes:

• Ensures Fluent custom events are registered only once globally (even if both Web and Server startup hooks run).
• Bridges Blazor’s overflowchange custom event to an internal fluentoverflowchange browser event while still dispatching the public overflowchange DOM event.
• Overrides fluent-tooltip’s showPopover() to no-op when the tooltip is disconnected, avoiding Chromium invalid-state exceptions.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/Core.Scripts/src/FluentUIWebComponentsOverride.ts	Adds a fluent-tooltip showPopover override that ignores stale callbacks after disconnect.
src/Core.Scripts/src/FluentUICustomEvents.ts	Wraps registerCustomEventType with global defineOnce and remaps Overflow’s browser event name to fluentoverflowchange.
src/Core.Scripts/src/Components/Overflow/FluentOverflow.ts	Dispatches both overflowchange and fluentoverflowchange events with identical payloads.

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