WebBrowser control blocks accelerators of buttons on form #8862

.NET version

.NET 6.0, .NET 7.0

Did it work in .NET Framework?

Yes

Did it work in any of the earlier releases of .NET Core or .NET 5+?

.NET 4.8

Issue description

See attached sample: I have a "System.Windows.Forms.WebBrowser" control on a UserControl.
The UserControl and the root form contain buttons with accelerator keys. In .NET6, the accelerators for the buttons don't work reliable.

Steps to reproduce

Focus the textbox on the UserControl, then press "Alt" and one of the accelerator keys "B" or "O".

• The button on the user control will be clicked when pressing the accelerator the second time. On first button press, nothing happens.
• The "OK" button on the root form is never called.

The sample also has target framework 4.8 to demonstrate that this it worked there.

WebBrowserTest.zip

The event "WebBrowserControl.PreviewKeyDown" is called twice for each button. This means I cannot handle a "Alt + accelerator" press myself (and search for a button with this accelerator).