TeachingTip does not display on the target control and IsOpen can't be set from markup

[lukeblevins]

Describe the bug
Targeting a teaching tip to a control may display the TeachingTip elsewhere.

Steps to reproduce the bug
I'm unaware of a pattern that can be replicated.

Expected behavior
The TeachingTip should mount/attach itself to the targeted control-in the correct position.

Screenshots
This screenshot shows the teaching tip, which is targeting the bottom of the "Navigate to a path..." TextBox displayed in an incorrect position.

Version Info

NuGet package version:
Microsoft.UI.Xaml 2.1.190405004

Windows 10 version	Saw the problem?
Insider Build (18362.30)	Yes
October 2018 Update (17763)
April 2018 Update (17134)
Fall Creators Update (16299)
Creators Update (15063)
Anniversary Update (14393)

Device form factor	Saw the problem?
Desktop	Yes
Mobile
Xbox
Surface Hub
IoT

Additional context
Code snippet of problem:

<TextBox Grid.Column="1" CornerRadius="0" KeyDown="VisiblePath_TextChanged" Style="{StaticResource TextBoxStyleForPathBar}" BorderThickness="1" x:Name="VisiblePath" Text="{x:Bind local:App.PathText.Text, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" FontFamily="Segoe UI" FontWeight="SemiBold" FontSize="14" ScrollViewer.VerticalScrollBarVisibility="Hidden" ScrollViewer.HorizontalScrollBarVisibility="Auto" HorizontalAlignment="Stretch" VerticalAlignment="Center" Padding="5" Margin="2,5" PlaceholderText="Navigate to a path...">
       <TextBox.Resources>
              <uilib:TeachingTip Target="{x:Bind VisiblePath}" x:Key="PathBarTeachingTip" Name="PathBarTip" PreferredPlacement="Bottom" Subtitle="Enter a full path or simply the name of a common location" Title="Access locations quickly">
                     <uilib:TeachingTip.IconSource>
                           <uilib:SymbolIconSource Symbol="Help"/>
                     </uilib:TeachingTip.IconSource>
               </uilib:TeachingTip>
       </TextBox.Resources>
</TextBox>

[jevansaks]

@duke7553 thanks for the bug report! I tried your snippet and wasn't able to repro. When are you setting IsOpen=true? I could believe there is a timing issue where perhaps the TextBox isn't at its final layout position when we try to calculate the TeachingTip position, but I'd like to make sure that's what you're seeing. Do you have an app we could install and debug through?

[lukeblevins]

Yes, I do have a public app that has this problem.

1. Check out the source code at the "newui" branch found here: https://github.com/duke7553/files-uwp/tree/newui
2. In the file ProHome.xaml.cs, find the constructor and set the PathBarTip.IsOpen property to true
3. You can now execute the app and discover the bug.

Thanks for your help.
UNRELATED: The sample app is a project of mine developed during my free time. Many components still don't work on the newui branch, so feel free to download a more stable release from the repo page if you're interested.

[lukeblevins]

I also noticed setting the IsOpen property from markup fails completely.

[lukeblevins]

@jevansaks ProHome.RibbonTeachingTip is the updated name in the project in case you were wondering.

[jevansaks]

Thanks! @StephenLPeters can you debug this project too?

[jevansaks]

2. In the file ProHome.xaml.cs, find the constructor and set the PathBarTip.IsOpen property to true

I think this is the issue. We need to defer calculating position and stuff until everything is loaded. I don't see a bug tracking this so we'll use this.

[jevansaks]

@duke7553 To work around this, don't set IsOpen until the Loaded event.

[lukeblevins]

@jevansaks Thanks! This did the trick.