Fix problem where TeachingTip would not update position when target has moved

[marcelwgn]

Description

Fix bug where moving of target of a TeachingTip would leave TeachingTip in place and possibly dangling separated from its target.

Motivation and Context

Fixes #1547

How Has This Been Tested?

Added new test.

Screenshots (if appropriate):

[kaiguo]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[marcelwgn]

It seems like some tests are failing now:
https://dev.azure.com/ms/microsoft-ui-xaml/_build/results?buildId=49051

However I was unable to reproduce those tests failing on my machine 🤔

[StephenLPeters]

@SavoySchuler FYI. I actually had this feature in developement for a long time, there is even a test hook which enables it, search the code for m_tipFollowsTarget to see. We decided during development that we did not want this behavior because when the target scrolls outside of the effective view port our tip would potentially point to the wrong piece of UI, our guidance specifies not to target an element in a scrollable surface with a teaching tip for exactly this reason. I think to fix #1547 we need to attach to the window's maximized event.

[StephenLPeters]

If we do decide to change the tip follows target behavior the control is set up such that changing the m_tipFollowsTarget boolean flag's default value from false to true will enable the feature.

[StephenLPeters]

    public void TipCanFollowTarget()

I think this test already does what you are testing for

---

Refers to: dev/TeachingTip/InteractionTests/TeachingTipTests.cs:187 in 45b682e. [](commit_id = 45b682e, deletion_comment = False)

[StephenLPeters]

It seems like some tests are failing now:
https://dev.azure.com/ms/microsoft-ui-xaml/_build/results?buildId=49051

However I was unable to reproduce those tests failing on my machine 🤔

The bulk of your test failures are the test app crashing on rs2-4 because the effectiveViewportChanged event you are attaching to is only available on rs5+. The rs5 and 19h1 failure in TipsWhichDoNotFitDoNotOpen I can't explain

[marcelwgn]

    public void TipCanFollowTarget()

I think this test already does what you are testing for

Refers to: dev/TeachingTip/InteractionTests/TeachingTipTests.cs:187 in 45b682e. [](commit_id = 45b682e, deletion_comment = False)

Thank you for pointing that out. Missed that there were already tests covering what I tried to test with that. 😅 I have removed the test now.

[StephenLPeters]

TeachingTipInResources [](start = 69, length = 22)

This has the same automation name as the other teaching tip on this page, I'd be surprised if this didn't cause test issues

[marcelwgn]

Interestingly this did not crash the tests. I guess since we don't have test that actually get the TeachingTips using their UIA name, no test is impacted by conflicting UIA names.

[StephenLPeters]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[StephenLPeters]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[msft-github-bot]

🎉Microsoft.UI.Xaml v2.3.191127001-prerelease has been released which incorporates this pull request.:tada:

Handy links:

• Release Notes
• Official Nuget Release