[dotnet-sdk-11.0.100-preview.3.26174.105] The radzen blazor menu cannot expand with error: Uncaught TypeError: t.DispatchMouseEvent is not a function.

[Junjun-zhao]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

After we retarget radzen blazor to .net11.0 and build with dotnet-sdk-11.0.100-preview.3.26174.105, we run the app and click to expand the menu, but the menu cannot expand and show error: Uncaught TypeError: t.DispatchMouseEvent is not a function.

Application Name: radzen-blazor
OS: Windows 11 25H2
CPU: X64
.NET Build Number: dotnet-sdk-11.0.100-preview.3.26174.105

GitHub Link: https://github.com/radzenhq/radzen-blazor

Or checking App Source from: (https://devdiv.visualstudio.com/DevDiv/_workitems/edit/2880585)

Verify Scenarios:
1). Windows 11 25H2 AMD64 + dotnet-sdk-11.0.100-preview.3.26172.108: Pass
2). Windows 11 25H2 AMD64 + dotnet-sdk-11.0.100-preview.3.26174.105: Fail
3). Windows 11 25H2 AMD64 + dotnet-sdk-11.0.100-preview.3.26179.102: Fail

Expected Behavior

The menu can be expanded.

Steps To Reproduce

1. Retarget the project to net11.0. (Replace net10 with net11 in the entire solution.)
   <TargetFrameworks>net11.0</TargetFrameworks>

2. Add PackageReference in Radzen.Blazor.csproj.

<PackageReference Include="Microsoft.AspNetCore.Components.Web" Condition="'$(TargetFramework)' == 'net11.0'" Version="11.*-*" />

3. Build the project RadzenBlazorDemos.Host with dotnet-sdk-11.0.100-preview.3.26174.105. (Add global.json: {"sdk": {"version": "11.0.100-preview.3.26174.105"}})
4. Lanuch RadzenBlazorDemos.Host.exe.
5. Go to http://localhost:5000/get-started.
6. Expand the “DataGrid” item.

Exceptions (if any)

The menu cannot expand with error in console:

blazor.web.js:1 Uncaught TypeError: t.DispatchMouseEvent is not a function
    at blazor.web.js:1:16005
    at blazor.web.js:1:18987
    at M (blazor.web.js:1:19374)
    at blazor.web.js:1:19424
    at Object.invokeWhenHeapUnlocked (blazor.web.js:1:186856)
    at blazor.web.js:1:191014
    at M (blazor.web.js:1:19414)
    at N (blazor.web.js:1:15485)
    at F.dispatchGlobalEventToAllElements (blazor.web.js:1:22166)
    at F.onGlobalEvent (blazor.web.js:1:21569)

.NET Version

11.0.100-preview.3.26174.105

Anything else?

dotnet --info

.NET SDK:
 Version:           11.0.100-preview.3.26174.105
 Commit:            499c5b40b9
 Workload version:  11.0.100-manifests.8fe6e2b8
 MSBuild version:   18.6.0-preview-26174-105+499c5b40b

Runtime environment:
 OS Name:     Windows
 OS Version:  10.0.26200
 OS Platform: Windows
 RID:         win-x64
 Base Path:   C:\Program Files\dotnet\sdk\11.0.100-preview.3.26174.105\

Host:
  Version:      11.0.0-preview.3.26174.105
  Architecture: x64
  Commit:       499c5b40b9

.NET SDKs installed:
  11.0.100-preview.3.26174.105 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 11.0.0-preview.3.26174.105 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 11.0.0-preview.3.26174.105 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 11.0.0-preview.3.26174.105 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

@dotnet-actwx-bot @dotnet/compat

[github-actions]

Triage Summary

Area: area-blazor — The error originates in blazor.web.js within the Blazor event dispatch infrastructure (dispatchGlobalEventToAllElements, onGlobalEvent, DispatchMouseEvent), which is part of the Blazor Web JS runtime.

Type: bug — A clear regression where a specific SDK update broke previously working functionality.

Regression Info

• Previously working version: dotnet-sdk-11.0.100-preview.3.26172.108
• Broken since: dotnet-sdk-11.0.100-preview.3.26174.105 (also confirmed broken in preview.3.26179.102)
• The Blazor JS runtime's DispatchMouseEvent function appears to have been removed or renamed between these two preview builds, causing a TypeError when Blazor attempts to dispatch mouse events (e.g., click to expand a menu item).

Potential Duplicates

• None found

Notes

• The error occurs in minified blazor.web.js at the event dispatch layer. The symbol DispatchMouseEvent being referenced as a function suggests a possible renaming or removal of this function during JS bundling/tree-shaking changes between the two preview builds.
• Reproduces with the third-party radzen-blazor library, but the root cause is in the Blazor web JS runtime — this is not a radzen-specific issue.
• The issue links to an internal ADO work item: (devdiv.visualstudio.com/redacted)

Generated by Issue Triage Agent for dotnet/aspnetcore for issue #66110 · ◷

[oroztocil]

This is related to a recent sequence of PRs that introduced new functions in the JS interop API (including DispatchMouseEvent mentioned in the error), and were later reverted. See:

• [blazor][wasm] JSExport for events #65897
• [blazor][wasm] Convert more interop to JSImport #65895
• [blazor][wasm] Revert JSExport for events (#65897) #66068
• [blazor][wasm] Revert Convert more interop to JSImport (#65895) #66069

As such, the problem should resolve itself in a newer build once all commits have flown properly.

@Junjun-zhao May I ask you for re-testing this with a current build (or wait some time and then re-test)?

[Junjun-zhao]

This is related to a recent sequence of PRs that introduced new functions in the JS interop API (including DispatchMouseEvent mentioned in the error), and were later reverted. See:

• [blazor][wasm] JSExport for events #65897
• [blazor][wasm] Convert more interop to JSImport #65895
• [blazor][wasm] Revert JSExport for events (#65897) #66068
• [blazor][wasm] Revert Convert more interop to JSImport (#65895) #66069

As such, the problem should resolve itself in a newer build once all commits have flown properly.

@Junjun-zhao May I ask you for re-testing this with a current build (or wait some time and then re-test)?

Sure. We will re-test with a new build next week.