Xamarin is Unstable and Unreliable

This issue is REPEATABLE! I have created a fresh new Xamarin Forms project and added 3 one after another with padding and background colors. I run the project on emulator and the last was displayed as expected.
Then I delete the last 2 leaving just one like the just like below. I build the project and no error was reported. When I run the project on emulator (Genymotion) I started getting this error: Xamarin.Forms.Xaml.XamlParseException:

Error occurred here:
[global::System.CodeDom.Compiler.GeneratedCodeAttribute("Xamarin.Forms.Build.Tasks.XamlG", "0.0.0.0")]
private void InitializeComponent() {
global::Xamarin.Forms.Xaml.Extensions.LoadFromXaml(this, typeof(MainPage));
}