[Windows] CollectionView GroupHeader doesn't fill space horizontaly

[Vroomer]

Description

GroupHeader doesn't fill available horizontal space even if you set HorizontalOptions="Fill". This is not a new bug, I noticed the behaviour in .NET 7 as well. Android is correct. iOS wasn't tested.

Steps to Reproduce

1. Load the repository and run the app.
2. Observe the spacing around yellow border.

Link to public reproduction project repository

https://github.com/Vroomer/MAUI-CollectionView-templates-bugs.git

Version with bug

8.0.0-rc.2.9511

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

8.0.0-rc.2.9511

Affected platforms

Windows

Affected platform versions

Windows SDK 10.0.19041.0

Did you find any workaround?

No response

Relevant log output

No response

We've added this issue to our backlog, and we will work to address it as time and resources allow. If you have any additional information or questions about this issue, please leave a comment. For additional info about issue management, please read our Triage Process.

[XamlTest]

Verified this on Visual Studio Enterprise 17.9.0 Preview 1(8.0.3). Repro on Windows 11, not repro on Android 14.0-API34 with below Project:
MauiApp10.zip

[BFuchshofer]

I also can reproduce this issue on .net 7 iOS. The group footer of the CollectionView is also affected. I can't get the header/footer positioned correctly. HorizontalOptions does nothing.

[Bloodyairtimer]

I have been able to 'fix' the issue by binding the WidthRequest of the template container to the Width of the Collectionview.

WidthRequest="{Binding Width, Source={x:reference collectionViewName}}"

As I don't want this binding on the other platforms I have a Headless contentview around it with only the above binding on the WinUI platform

[EmanterolaDN]

Even is duplicate of #18699 Here is set a workaround by @Bloodyairtimer .
I've recently applied it and it's working... Thx btw!

[DanTravison]

I'm seeing this same behavior on Windows 11 with Maui build 9.0.50.