ScrollHeader with a TextBox inside it gets focus on tapping anywhere on header

[touseefbsb]

I'm submitting a...

Bug report (I searched for similar issues and did not find one)

Current behavior

While using ScrollHeader with AdaptiveGridView. If we put a TextBox/AutoSuggestBox in the header, the autosuggestbox/textbox gets focus no matter where the user taps on the header and to make it loose its focus, user has to tap outside the header. the issue goes away if normal header is used without ScrollHeader.

Expected behavior

the AutoSuggestBox/TextBox should only get focus when tapped only on it and not by tapping anywhere else on the header.

Minimal reproduction of the problem with instructions

I have made a repo to reproduce the issue : https://github.com/touseefbsb/ScrollHeaderBug
it has 2 empty AdaptiveGridView controls with headers 1 has AutoSuggestBox and other has TextBox in its header and both also have a TextBlock to make some additional space in the header.

1. Run the app.
2. Tap on anywhere on the headers except the textbox itself and textbox will get the focus, tap outside the header to lose its focus.

Environment

Package Version(s): 4.0

Windows 10 Build Number:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [x] October 2018 Update (17763)
- [ ] Insider Build (build number: )

App min and target version:
- [ ] Fall Creators Update (16299)
- [x] April 2018 Update (17134)
- [x] October 2018 Update (17763)
- [ ] Insider Build (xxxxx)

Device form factor:
- [x] Desktop
- [ ] Mobile
- [ ] Xbox
- [ ] Surface Hub
- [ ] IoT

Visual Studio 
- [x] 2017 (version: ) 15.8.7
- [ ] 2017 Preview (version: )

[nmetulev]

This is an issue with ScrollViewer (it's used in the ScrollHeader). For example, the following has the exact same behavior:

<ScrollViewer Background="Red">
    <StackPanel>
        <TextBox Width="220" PlaceholderText="I am a textbox"/>
        <TextBlock TextWrapping="WrapWholeWords" FontSize="28"
                              Text="The TextBox above me will get focused even if you click on me "/>
    </StackPanel>
</ScrollViewer>

Not sure if there is a way to fix this without removing the ScrollViewer, some investigation is needed. Open to anyone to investigate further.

[touseefbsb]

if the issue is in ScrollViewer which is a platform control and is usually hard to get a fast change or fix in them, would it be possible to request winUI team to make the fix and ship an improved ScrollViewer in winUI library? Would that make sense here?

[nmetulev]

I might be wrong, but I don't think there is a ScrollViewer in WinUI.

[JustinXinLiu]

There was one in the WinUI prerelease but got taken out. It’s probably not ready yet.