MainView.ux

<App Model="MainView" Background="#fefefe">
    <StatusBarBackground Background="#f53b50" Alignment="Top"/>    

    <Rectangle Layer="Background" ux:Name="bg" Alignment="Left" Width="33%" Color="MainColor">
        <WhileTrue Value="{pageIndex} == 1">
            <Change bg.Width="67%" Duration=".3" Easing="QuadraticInOut"/>
        </WhileTrue>
        <WhileTrue Value="{pageIndex} == 2">
            <Change bg.Width="100%" Duration=".3" Easing="QuadraticInOut"/>
        </WhileTrue>
    </Rectangle>
    
 <ClientPanel>

        <TopBar />

        <PageControl ActiveIndex="{pageIndex}" Interaction="None" InactiveState="Collapsed" CachingMode="Never">
            <Deferred>
                <CategoriesView />
                <CategoryDetailsView  />
                <ShoppingCartView /> 
            </Deferred>
        </PageControl>
    </ClientPanel>    
</App>