DevTools should not add visual elements to its logical tree

[pavelovcharov]

What does the pull request do?

This PR makes sure that the visual elements are not added to the DevTools logical tree.

What is the current behavior?

Currently in 11.2, visual elements can be added to the DevTools logical tree. This can causes the app's visual tree to break.

    <TabControl>
        <TabItem Header="Item1">
            <Button>button1</Button>
        </TabItem>
        <TabItem Header="Item2">
            <Button>button2</Button>
        </TabItem>
    </TabControl>

AvaloniaApplication5_bAxslwekDg.mp4

What is the updated/expected behavior with this PR?

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

Checklist

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

Breaking changes

Obsoletions / Deprecations

Fixed issues

[avaloniaui-bot]

You can test this PR using the following package version. 11.3.999-cibuild0053115-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[cla-avalonia]

• All contributors have signed the CLA.

[pavelovcharov]

@cla-avalonia agree

[maxkatz6]

What problem does it solve?

[avaloniaui-bot]

You can test this PR using the following package version. 11.3.999-cibuild0053117-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[pavelovcharov]

@maxkatz6 I've noticed a rather strange bug in v.11.2 - visual elements disappear from the visual tree after inspection with DevTools.

    <TabControl>
        <TabItem Header="Item1">
            <Button>button1</Button>
        </TabItem>
        <TabItem Header="Item2">
            <Button>button2</Button>
        </TabItem>
    </TabControl>

AvaloniaApplication5_bAxslwekDg.mp4

I think it happens because the ContentControl in the ControlDetailsView puts its content in its logical tree. So, I did this PR to make sure that I got it right.

[avaloniaui-bot]

You can test this PR using the following package version. 11.3.999-cibuild0053117-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[avaloniaui-bot]

You can test this PR using the following package version. 11.3.999-cibuild0053127-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]