I'm trying to call command which is bindable in tapgesture...
Why TabTappedCommand doesn't do nothing...

IrrigNetPage.xaml

```
        <StackLayout BackgroundColor="{Binding SelectedTabColor}"
                     x:Name="StackService">
            <StackLayout.GestureRecognizers>
                <TapGestureRecognizer Command="{Binding TabTappedCommand}" CommandParameter="service"/>
            </StackLayout.GestureRecognizers>
            <Image Source="{Binding ServiceTabIcon}"
                   HorizontalOptions="Start"
                   VerticalOptions="Center" 
                   WidthRequest="16"
                   HeightRequest="16"
                   Aspect="AspectFit"                       
                   x:Name="ServiceIcon"/>
            <Label Text="{i18n:Translate Service}"
               VerticalOptions="FillAndExpand" 
               HorizontalOptions="FillAndExpand"
               VerticalTextAlignment="Center"
               HorizontalTextAlignment="Start"
               TextColor="{Binding SelectedTabTextColor}"
               x:Name="ServiceText"/>
        </StackLayout>

```

IrrigNetViewModel.cs

```
public string ServiceTabIcon { get; set; } = "services_sel.png";
public string LocationTabIcon { get; set; } = "location.png";
public string MapTabIcon { get; set; } = "location.png";
public string ListHederIcon { get; set; } = "service_irrig.png";

public ICommand TabTappedCommand { get; }

 public IrrigNetViewModel()
 {
     TabTappedCommand = new Command((tabName) => OnTapClicked(tabName.ToString()));
 }

    private void OnTapClicked(string tabName)
    {
        string serviceBlackIcon = "services.png";
        string locationWhiteIcon = "location_sel.png";
        string mapWhiteIcon = "location_sel.png";

        if (tabName == "service")
        {
            ServiceTabIcon = "services_sel.png";
            LocationTabIcon = "location.png";
            MapTabIcon = "location.png";
        }

        else if (tabName == "location")
        {
            ServiceTabIcon = "services.png";
            LocationTabIcon = "location_sel.png";
            MapTabIcon = "location.png";
        }
        else
        {
            ServiceTabIcon = "services.png";
            LocationTabIcon = "location.png";
            MapTabIcon = "location_sel.png";
        }
    }

```

So, point is to change icons of selected stackLayout (and back to default icons when it's unselected) but for some reason `TabTappedCommand` doesn't work... What I'm missing...?