This app shows what happens if the shadowRoot is initialized without delegatesFocus: true and there are focusable elements inside of the custom element.
If the PR will be merged, there is already a setting in the HelloWorld.ce.vue component that will allow the focus to be properly set.
defineOptions({
shadowRootOptions: { delegatesFocus: true },
})More information on MDN: https://developer.mozilla.org/en-US/docs/Web/API/ShadowRoot/delegatesFocus