Variable definied in XAML - no intellisense support in C# code behind?

Hello,

I'm trying to start developing with Xamarin.Forms and Xamarin Studio. I define a variable in XAML, then try to acesss it at code behind but intellisense is not working, the variable is shown in red. App compiles and works but it's a pain not to have intellisense in code behind.

Look at attached images to see it.

XAML

Code:

Regards