[sheiksyedm]

Note

Are you waiting for the changes in this PR to be merged?
It would be very helpful if you could test the resulting artifacts from this PR and let us know in a comment if this change resolves your issue. Thank you!

Issue Details

On Windows, a regular WebView renders blank when used alongside a HybridWebView. This regression was originally reported in #34558 and reported again in #39297 after the previous fix, #35092, was reverted by #35814 because of HybridWebView device-test failures in CI.

The reported two-window scenario was reproduced in Sandbox using local HTML to avoid network dependencies. In both initialization orders, the first control loaded successfully while the second failed WebView2 initialization with COMException 0x8007139F.

Root Cause

WinUI initializes its default WebView2 environment with Language set to the first entry in Windows.Globalization.ApplicationLanguages.Languages. HybridWebView creates an explicit environment without applying the same language default.

WebView2 controls sharing a user data folder require compatible browser-process environment options. The different language defaults make these environments incompatible, preventing the second control from initializing.

Fix Details

Apply WinUI's application-language default when the HybridWebView environment language is unspecified.

• Preserve explicitly configured environment languages.
• Preserve custom user data folders, profiles, and other environment/controller settings.
• Retain a single explicit environment/controller initialization path.
• Leave regular WebView initialization and non-Windows implementations unchanged.

Unlike the reverted fix, this does not switch between default and explicit initialization depending on whether settings are customized. It resolves the underlying language mismatch for both default and customized initialization.

Validation

Added focused Windows device tests covering:

• Default coexistence in both initialization orders.
• Coexistence with a custom HybridWebView profile.
• Coexistence with explicitly supplied environment options whose language is unspecified.
• Preservation of an explicitly configured language.

Issues Fixed

Fixes #34558
Fixes #39297

[github-actions]

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.sh | bash -s -- 39512

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.ps1) } 39512"

[azure-pipelines]

Azure Pipelines:
Successfully started running 1 pipeline(s).
There may be pipelines that require an authorized user to comment /azp run to run.

[Copilot]

🔵 Needs a closer look

Windows device-test results remain unverified, and the previous fix was reverted after CI failures.

No open issues 🎉

What changed in this PR

Addresses blank Windows WebViews alongside HybridWebView by aligning their default WebView2 environment languages.

Changes:

• Apply the application language when HybridWebView has no explicit language.
• Preserve custom settings and the existing initialization path.
• Add Windows tests for coexistence and explicit-language preservation.

File	Description
src/​Core/​src/​Handlers/​HybridWebView/​HybridWebViewHandler.Windows.cs	Aligns the default environment language with WinUI.
src/​Controls/​tests/​DeviceTests/​Elements/​HybridWebView/​HybridWebViewTests_Initialization.Windows.cs	Tests preservation of an explicit language.
src/​Controls/​tests/​DeviceTests/​Elements/​HybridWebView/​HybridWebViewTests_Coexistence.Windows.cs	Tests both initialization orders and customized settings.

_{Review effort: Balanced}