Revert "sandbox demo of shutdown cancel."
Revert "sandbox demo of shutdown cancel."

This reverts commit 851baa6537859ea6df8d774911003c97aa1e1bf8.

wieslawsoltes/Perspex,SuperJMN/Avalonia,jkoritzinsky/Avalonia,wieslawsoltes/Perspex,SuperJMN/Avalonia,wieslawsoltes/Perspex,AvaloniaUI/Avalonia,jkoritzinsky/Avalonia,AvaloniaUI/Avalonia,grokys/Perspex,AvaloniaUI/Avalonia,grokys/Perspex,Perspex/Perspex,SuperJMN/Avalonia,AvaloniaUI/Avalonia,jkoritzinsky/Avalonia,SuperJMN/Avalonia,jkoritzinsky/Avalonia,AvaloniaUI/Avalonia,SuperJMN/Avalonia,AvaloniaUI/Avalonia,wieslawsoltes/Perspex,jkoritzinsky/Avalonia,SuperJMN/Avalonia,SuperJMN/Avalonia,jkoritzinsky/Avalonia,wieslawsoltes/Perspex,wieslawsoltes/Perspex,Perspex/Perspex,AvaloniaUI/Avalonia,jkoritzinsky/Perspex,jkoritzinsky/Avalonia,wieslawsoltes/Perspex