NativeFrame sample clicking behind ui components

[Xiaoy312]

Current behavior

With "native frame" opened, ui components behind the frame can still be interacted with:

^ when clicking on where "Show Sample" is, the frame blinked every time, not just the first time. the recording just failed to capture that.

Expected behavior

^ should not happen

How to reproduce it (as minimally and precisely as possible)

1. checkout this repo @ e3327ab
2. launch the sample app on skia
3. go to: Controls\NativeFrame
4. click on "Show Sample"
   ^ and dont move the cursor
5. click on the same spot again
   ^ notice that the entire page will blink (the frame is reloaded/opened again)
6. click randomly on where the navigation view menu items are
7. click on "Exit Sample"
   ^ notice that we are no longer on the "NativeFrame" page anymore, if you manage to hit anything on step6

Affected platform(s): // may be reproducible on other platforms as well

• WebAssembly
• Android
• iOS
• macOS (AppKit)
• Mac Catalyst
• Skia
  • WPF
  • GTK (Linux)
  • Linux Framebuffer
  • Tizen
• Windows

IDE: Visual Studio 2022
Relevant plugins: N/A

Anything else we need to know?