BorderColor isn't working

Hey, I'm really bored to loose time with that, but I'm stuck with the BorderColor of a button and the OutlineColor of a Frame.

I tried both in xaml file but they aren't showing on my Android application.

This is my code :
<ContentPage.Resources> <ResourceDictionary> <Style x:Key="buttonStyle" TargetType="Button"> <Setter Property="BorderColor" Value="{x:Static statics:Colors._Accent}" /> <Setter Property="BorderRadius" Value="5" /> <Setter Property="BorderWidth" Value="5" /> <Setter Property="BackgroundColor" Value="{x:Static statics:Colors._Primary}" /> <Setter Property="WidthRequest" Value="200" /> <Setter Property="TextColor" Value="Teal" /> </Style> </ResourceDictionary> </ContentPage.Resources>

And

<ContentPage.Content> <StackLayout Orientation="Vertical" VerticalOptions="Start" BackgroundColor="{x:Static statics:Colors._PageBackground}" > <Frame OutlineColor="#1961ac"> <Label Text="Test"/> </Frame> <Button Text="Test" Style="{StaticResource buttonStyle}" ></Button> </StackLayout> </ContentPage.Content>

I use the last pre version of Xamarin Forms and the AppCompat theme.