Xaml Islands Fixes for FocusManager.GetFocusedElement and ContentDial…

[azchohfi]

Fixes #3340 #3216 #3205

Fixed issues with any class using FocusManager.GetFocusedElement when running inside the context of a Xaml Island, as well as one last issue with TextToolbar's ContentDialog not having it's XamlRoot set, also in the context of a Xaml Island.

PR Type

What kind of change does this PR introduce?

• Bugfix

What is the current behavior?

FocusManager.GetFocusedElement() always returns null when executed in the context of a Xaml Island, so any class that leverages this method will not work properly on Xaml Islands, as reported in #3340.

What is the new behavior?

If XamlRoot is available, calls the new overload FocusManager.GetFocusedElement(XamlRoot), with the appropriate XamlRoot.

PR Checklist

Please check if your PR fulfills the following requirements:

• Tested code with current supported SDKs
• Pull Request has been submitted to the documentation repository instructions. Link:
• Sample in sample app has been added / updated (for bug fixes / features)
  • Icon has been created (if new sample) following the Thumbnail Style Guide and templates
• Tests for the changes have been added (for bug fixes / features) (if applicable)
• Header has been added to all new source files (run build/UpdateHeaders.bat)
• Contains NO breaking changes

[ghost]

Thanks azchohfi for opening a Pull Request! The reviewers will test the PR and highlight if there is any conflict or changes required. If the PR is approved we will proceed to merge the pull request 🙌

[michael-hawker]

@azchohfi can you link to the blog post here or in the issue with the list of all the changes XAML Islands needs? Will be good for future reference to have it linked to here if folks stumble upon this in the future.

[michael-hawker]

Couple of minor issues/comments on manual tests, but otherwise looks great, thanks!

[Kyaa-dost]

Looks good 🚀 🚀