Fix DataContext not getting GC'd/Finalized. closes #12123

[flexxxxer]

What does the pull request do?

Now Window.DataContext getting GC'd/Finalized after window close and GC.Collect call.

What is the current behavior?

Window.DataContext not getting GC'd/Finalized after window close and GC.Collect call.

What is the updated/expected behavior with this PR?

Window.DataContext getting GC'd/Finalized after window close and GC.Collect call.

How was the solution implemented (if it's not obvious)?

To Avalonia.Controls.TopLevel.HandleClosed method body was added Avalonia.Controls.TopLevel.StopRendering method call.

Checklist

• Added unit tests (if possible)?
• Added XML documentation to any related classes?
• Consider submitting a PR to https://github.com/AvaloniaUI/Documentation with user documentation

Breaking changes

None.

Obsoletions / Deprecations

None.

Fixed issues

#12123

[avaloniaui-team]

You can test this PR using the following package version. 11.0.999-cibuild0038306-beta. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[timunie]

Can you check if it also fixes #8240?

[avaloniaui-team]

You can test this PR using the following package version. 11.0.999-cibuild0038328-beta. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[flexxxxer]

Can you check if it also fixes #8240?

I will take a look

[flexxxxer]

Can you check if it also fixes #8240?

No, when MS Windows Narrator is turn ON. I won't be making fix changes #8240 in this pull request

[maxkatz6]

Thank you!