How to unfocus from a WebView in UWP - webview

Question

I'm working on a UWP app that hosts a WebView which runs in a separate process.
var webView = new Windows.UI.Xaml.Controls.WebView(WebViewExecutionMode.SeparateProcess)
This results in a behavior that if the WebView has the focus, the containing app can't regain the focus by itself by simply trying to focus on a UI element.
The app supports keyboard shortcuts which may result in different elements getting the focus, but it's not working correctly when the focus is captured by the WebView. The target element seems to be getting the focus but it seems as if the process itself is not activated (as the real focus resides in a different process I suppose...).
I'm currently trying to activate the app programmatically through protocol registration in an attempt to regain focus.
I added a declaration in the app manifest for a custom protocol mycustomprotocol coupled with the following activation overload
protected override void OnActivated(IActivatedEventArgs args)
{
if (eventArgs.Uri.Scheme == "mycustomprotocol")
{ }
}
And the following code to invoke the activation:
var result = await Windows.System.Launcher.LaunchUriAsync(new Uri("mycustomprotocol:"));
Seems to be working only on some computers, on others (not while debugging the app, only when executed unattached) instead of regaining focus the app's taskbar icon just flashes orange.
I've created a sample project showing the problem and the semi working solution here
Any insight on any of this would be great.

Answer 1

I can reproduce your issue. I found that when we switch the focus with the mouse, the focus can be transferred to the TextBlock. So you could solve this question through simulating mouse input.
Please use the following code to instead FocusTarget.Focus(FocusState.Programmatic).
As follows:
InputInjector inputInjector = InputInjector.TryCreate();
var infoDown = new InjectedInputMouseInfo();
// adjust your mouse position to the textbox through changing infoDown.DeltaX,infoDown.DeltaY
infoDown.DeltaX = 10; //change
infoDown.DeltaY = -150; //change
infoDown.MouseOptions = InjectedInputMouseOptions.LeftDown;
var infoUp = new InjectedInputMouseInfo();
infoUp.DeltaX = 0;
infoUp.DeltaY = 0;
infoUp.MouseOptions = InjectedInputMouseOptions.LeftUp;
inputInjector.InjectMouseInput(new[] { infoDown, infoUp });
Note: If you use the input injection APIs, you need to add inputInjectionBrokered Capabilitiy in your Package.appxmanifest.
But this Capabilitiy is a restricted Capabilitiy, you can’t publish this app in store, which can’t pass the verification.

Answer 2

I've been in discussions with a WebView software engineer. The problem is that the separate process still wants to own focus if you try to move the focus away from the webview. His solution is to ask the other process' web engine to give up focus with the following call:
_= webView.InvokeScriptAsync("eval", new string[] { "window.departFocus('up', { originLeft: 0, originTop: 0, originWidth: 0, originHeight: 0 });" });
You can call it before trying to change the focus to your target. I ran various tests and it works consistently.