The call is ambiguous between the following methods or properties...

Hello,

I have started a new Xamarin.Forms project and after upgraded Xamarin.Forms package (3.0.0.446417), I got this warning on InitializeComponent method call in App.xaml.cs (The call is ambiguous between the following methods or properties: 'App.InitializeComponent()' and 'App.InitializeComponent()') or in pages ((The call is ambiguous between the following methods or properties: 'MyPage.InitializeComponent()' and 'MyPage.InitializeComponent()')).
This warning doesn't appear for next pages I have newly created.
Any idea?

Thanks.