bug(ContextMenu): positioning fails in release configuration on Android in a dotnet MAUI app

[peereflits]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I'm using BootstrapBlazor in a dotnet MAUI app (net10) with a BlazorWebView.
In the app a ContextMenu is being used.

When I test the app in debug mode on an Android device the context menu behaves as expected.
But when I test the app in release mode on an Android device the context menu is always rendered in the bottom-left corner of the screen.

Debug mode

Release mode

I created an example app to demonstrate the issues. See the attachment.

BBContextMenu.zip

I tested this on:

• Nokia Phone 7.2 (Android version 11)
• Nokia Tablet T21 (Android version 14)

It works well on a Windows device.
I'm not yet able to test this on an Apple device.

Expected Behavior

The context menu should be rendered near the touched location in release mode, instead of the bottom left corner.

Interactive render mode

Interactive WebAssembly (Client-side rendering (CSR) using Blazor WebAssembly)

Steps To Reproduce

1. Connect an Android device to your Dev machine
2. Open this project in Visual Studio (2026)
3. Set the configuration to "Debug"
4. Run the app on your local connected device

5. Confirm that the context menu behaves normal
6. Switch the configuration to "Release"
7. Run the app on your local connected device
8. Click in the text. The context menu appears on the screen in the bottom-left corner. If you don't see a context menu swipe to the bottom of the screen.

.NET Version

NET10.0

Anything else?

IDE: Visual Studio 2026
.NET Version: 10
BootstrapBlazor Version: 10.2.0
App type: .NET MAUI Hybrid Blazor

I haven't searched the existing issues as I can't read Chinese.

[bb-auto]

@peereflits Thank you for filing this issue. In order for us to investigate this issue, please provide a minimalistic repro project that illustrates the problem.

[peereflits]

See repo: https://github.com/peereflits/BootstrapBlazorContextMenuIssue7450

It is the same as the attachment in the description

[ArgoZhang]

@peereflits hi. thank you for contacting us. We'll investigate and get back to you.

[ArgoZhang]

@peereflits hi. sorry for the delayed reply. it's repro., but I still don't know where the problem lies or how to fix it.

[peereflits]

@ArgoZhang Hi,
I did some investigation and I can point only towards where the issue might be.

In my app I enabled the web Developer tools, both in Debug and Release:

    builder.Services.AddBlazorWebViewDeveloperTools();

I deployed a debug version of my app to an Android device and started to inspect a page with a contect menu.

Debug

Than I deployed a release version of that app to the same Android device and started to inspect the same page.

Release

Searching in the source code I suspect the issue, is in ContextMenu.razor.js, somewhere around line 78 - 85.

    const pos = await computePosition(vl, menu, {
        placement: 'bottom-start'
    })

    Object.assign(menu.style, {
        left: `${pos.x}px`,
        top: `${pos.y}px`,
    })

I assume that the Object.assign fails because computePosition somehow errors/void/null in release mode (on Android).
I hope this helps.