PP/AlenaTest/MainWindow.xaml

<Window x:Class="AlenaTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:AlenaTest"
        mc:Ignorable="d"
        Title="Тестирование" MinHeight="519" MinWidth="391" Width="791" Height="519">
    <Grid>
        <Frame NavigationUIVisibility="Hidden" Source="Pages/StartPage.xaml"/>
    </Grid>
</Window>