Input rendered in TWebBrowser using Edge keeps unfocusing when clicked

In my FMX application I have a webpage that I'm rendering inside a TWebBrowser. The webpage has a simple <input>, but on Windows if I click the input it focuses and immediately unfocuses. After clicking a seemingly random number of times it stops unfocusing.

But if I AltTab to another application and back the problem happens again.

I have a very simple setup that reproduces the issue. I have an FMX application with just this code added:

procedure TForm1.FormCreate(Sender: TObject);
begin
  var browser := TWebBrowser.Create(Self);
  browser.WindowsEngine := TWindowsEngine.EdgeOnly;
  browser.Align := TAlignLayout.Client;
  browser.URL := 'http://localhost:8000/test.html';
  Self.AddObject(browser);
end;

I also have a test.html file with this content:

<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Test</title>
  </head>
  <body>
    <input type="text" name="test">
  </body>
</html>

I'm using Python to start a HTTP server so I can load test.html in the browser.

I've also added WebView2Loader.dll so .EdgeOnly works. Now if I use .IEOnly I don't have the issue, but I need to use .EdgeOnly for other stuff. It's not an option for me to use .IEOnly.

Anybody had this issue before?

Update: If I have a second screen connected to my laptop the issue does not happen.

Solution

Seems to be a bug in FMX.WebBrowser.Win

I found that if I comment out SetFocus call in code below

FWebViewController.Add_GotFocus(
  Callback<ICoreWebView2, IUnknown>
    .CreateAs<ICoreWebView2FocusChangedEventHandler>(
      function(const WebView: ICoreWebView2; const Args: IUnknown): HResult; stdcall
      begin
        Result := S_OK;
        FWebViewFocusEventActive := True;
        SetFocus;
        FWebViewFocusEventActive := False;
      end
    ),
    FGotFocusToken);

it works.

SetFocus looks like this

procedure TWinPresentation.SetFocus;
begin
  Winapi.Windows.SetFocus(Handle);
end;

Compared to vcl version in VCL.Edge which does this

FWebViewController.Add_GotFocus(
  Callback<ICoreWebView2, IUnknown>
    .CreateAs<ICoreWebView2FocusChangedEventHandler>(
      function(const WebView: ICoreWebView2; const Args: IUnknown): HResult; stdcall
      begin
        Result := S_OK;
        FWebViewFocusEventActive := True;
        DoEnter;
        FWebViewFocusEventActive := False;
      end
    ), FGotFocusToken);

procedure TCustomEdgeBrowser.DoEnter;
begin
  inherited;
  if not FWebViewFocusEventActive and (FWebViewController <> nil) then
    ProcessHResult(
     WebViewController.MoveFocus(COREWEBVIEW2_MOVE_FOCUS_REASON_PROGRAMMATIC));
end;

As you can see vcl version uses FWebViewFocusEventActive to skip changing focus on gotfocus event handler call but fmx version does set focus. So I think they wrongly copied vcl behavior here.

I'll make a bug report for this.