Panel.ZIndex does not work when there is a WindowsXamlHost control

[chanallenk]

Issue

In WPF when using WindowsXAMLHost, since there is no way to put WPF controls inside of UWP, I tried to put the WPF control on top of the WindowsXAMLHost as a workaround, but unfortunately this does not work, even when using Panel.ZIndex. While I kind of understand why it doesn't work (due to the nature of how XAML Islands host its UWP controls), it would be a very useful feature as a workaround to not being able to put WPF controls inside of a UWP control.

Environment

Nuget Package(s): 

Package Version(s): 

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

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

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

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

[Bmartin2013]

@chanallenk Hi! thanks for submitting this issue! For the next time, please follow the current WindowsCommunityTemplate repo template to submit your issue, this will make much easier to track and solve it as well. Second, do you have a sample app to reproduce this issue? Thanks again

[chanallenk]

WpfApp1XamlIsland.zip
@Bmartin2013 Hello, apologies this is my first time with an account in this site. I have attached a sample app, you can see this behavior in MainWindow.xaml.

[michael-hawker]

@chanallenk this is a platform limitation. Can you file a request in the WinUI repo? Thanks.