Fix UIA navigation for TabControl

[SergeySmirnov-Akvelon]

Fixes #3058

Related issue: #3421

Proposed changes

• The issue is reproduced because the old logic sometimes returned incorrect results for "NextSibling" and "PreviousSibling", which led to incorrect shortcuts behavior. To fix the issue, UIA support was added in which we return the correct results
• Updated "SupportsUiaProviders" flag.
• Added and implemented accessible objects for the TabControl and TabPage
• Added unit tests.
• Fixed issue with Narrator

Customer Impact

Before fix:
Shortcuts in some cases did not work for TabControl

After fix:

Regression?

• No

Risk

• Minimal

Test methodology

• CTI team
• Unit tests

Accessibility testing

• Narrator
• Accessibility Insights
• Inspect

Test environment(s)

• Microsoft Windows [Version 10.0.19041.388]
• .NET Core SDK: 6.0.100-preview.3.21202.5

Microsoft Reviewers: Open in CodeFlow

[vladimir-krestov]

Fix that:

[dreddy-work]

@Tanya-Solyanik , can you take a final look at this?

[RussKie]

👍 with few comments

[RussKie]

redundant

[Tanya-Solyanik]

@dreddy-work - what is the appropriate label for new public surface.

Looks good, please see my comments though.

[RussKie]

what is the appropriate label for new public surface.

We're adding overrides here, which is acceptable; and thus we don't treat these as "new API", which require an API Review Board approval, documentations, etc.

[Tanya-Solyanik]

@RussKie - Overrides require new documentation topics, are they generated automatically?

[Tanya-Solyanik]

Please add a test to see if clients are listening.

[RussKie]

Overrides require new documentation topics, are they generated automatically?

I believe the override docs are generated automatically. @gewarren @carlossanlop is this correct?

[gewarren]

Overrides require new documentation topics, are they generated automatically?

I believe the override docs are generated automatically. @gewarren @carlossanlop is this correct?

Yes the override methods will appear on the main page for the type, like this: https://docs.microsoft.com/en-us/dotnet/api/system.diagnostics.metrics.observablecounter-1?view=net-6.0#methods

[dreddy-work]

LGTM.

[Tanya-Solyanik]

What happens when we hit the spinner control? Suppose we have more tab headers than fits into the control width, then we show a left/right arrows to navigate between the tab headers. Do we hit-test those arrows correctly?

[SergeySmirnov-Akvelon]

I have investigated this question and did not find direct access to the Spinner from the TabControl. We are now using the native Spinner implementation. I have not seen any difference in behavior since .NET Framework 4.7.2, except that now the Spinner is displayed first in the list of control elements, and not second as in .NET Framework 4.7.2. How critical do you think this is?

[Tanya-Solyanik]

Let's keep the hierarchy as is and follow up with Ryan. We can address this separately.

[Tanya-Solyanik]

The difference between UIA clients listening and AO create APIs is that the former will force creation of AO if AT (or touch driver) is listening but the object had not been created yet. This might be desired if tab is the first object accessed by narrator. Note that touch driver needs AO created to work as well as AT does.

[Tanya-Solyanik]

Looks good to me, please get a review from Vladimir and follow up with Ryan if we have to create a custom provider for the spinner control.

[dreddy-work]

@vladimir-krestov , I merged this. If you have further feedback, please feel free to update this and @SergeySmirnov-Akvelon will update them in the next PR along with the pending investigation.