[Problem/Bug]: Default context menu items disappear from PDF viewer when using ContextMenuRequested event

[philipp-naused]

What happened?

The default context menu items Back, Forward, and Refresh disappear from the context menu of the PDF viewer when an event handler is added to the CoreWebView2.ContextMenuRequested event.
This occurs even when an empty event handler is used.

view.CoreWebView2.ContextMenuRequested += (s, args) => { };

Before:

After:

Importance

Moderate. My app's user experience is affected, but still usable.

Runtime Channel

Stable release (WebView2 Runtime)

Runtime Version

139.0.3405.102

SDK Version

1.0.3240.44

Framework

Winforms

Operating System

Windows 11

OS Version

26100.4652

Repro steps

Add an empty event handler to the CoreWebView2.ContextMenuRequested event and open a PDF file.

view.CoreWebView2.ContextMenuRequested += (s, args) => { };

Repros in Edge Browser

No, issue does not reproduce in the corresponding Edge version

Regression

Don't know

Last working version (if regression)

No response

[chetanpandey1266]

Does this happen only for pdf viewer? Also it would be great if you can share a small sample app reproducing this behaviour.

[philipp-naused]

@chetanpandey1266 As far as I can tell, this only happens to PDFs. HTML pages are not affected.
I don't know what other types of page viewers there are that I could test.

#:package Microsoft.Web.WebView2@1.0.3405.78
#:property TargetFramework=net8.0-windows
#:property PublishAOT=false
#:property UseWindowsForms=true

using Microsoft.Web.WebView2.WinForms;

class Program
{
    [STAThread]
    private static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new Form1());
    }
}

class Form1 : Form
{
    public Form1()
    {
        Controls.Add(webView);
        InitializeAsync();
    }

    readonly WebView2 webView = new()
    {
        Dock = DockStyle.Fill,
    };

    async void InitializeAsync()
    {
        await webView.EnsureCoreWebView2Async(null);
        webView.CoreWebView2.ContextMenuRequested += (s, args) => { }; // comment out this line to make the bug disappear
        webView.Source = new Uri("https://arxiv.org/pdf/2508.16579"); // arbitrary PDF
    }
}

[chetanpandey1266]

I'm able to repro this issue. Will work on it and notify you once I know the root cause.