MainWindow.xaml

<Window x:Class="TabControlzEXExample.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:cons="urn:controlzex"
        xmlns:local="clr-namespace:TabControlzEXExample"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Window.DataContext>
        <local:MainWindowViewModel />
    </Window.DataContext>
    <Window.Resources>
        <DataTemplate x:Key="TabBrowserDataTemplate"
                      DataType="{x:Type local:BrowserTabItemViewModel}">
            <Grid>
                <Grid.RowDefinitions>
                    <RowDefinition Height="30" />
                    <RowDefinition Height="*" />
                </Grid.RowDefinitions>
                <Button Grid.Row="0"
                        Content="Main Tab Button" />
                <local:BrowserTabItemUC  Grid.Row="1" />
            </Grid>
        </DataTemplate>
        <DataTemplate x:Key="NewTabBrowserDataTemplate"
                      DataType="{x:Type local:BrowserTabItemViewModel}">
            <Grid>
                <Grid.RowDefinitions>
                    <RowDefinition Height="30" />
                    <RowDefinition Height="*" />
                </Grid.RowDefinitions>
                <Button Grid.Row="0"
                        Content="Other Button" />
                <local:BrowserTabItemUC  Grid.Row="1" />
            </Grid>
        </DataTemplate>
        <local:TabControlDataTemplateSelector x:Key="selector"
                                              WPFTabBrowserDataTemplate="{StaticResource TabBrowserDataTemplate}"
                                              NewWPFTTabBrowserDataTemplate="{StaticResource NewTabBrowserDataTemplate}" />
       
    </Window.Resources>
    <Grid>
        <!--<cons:TabControlEx x:Name="BrowserTabControl"
                           SelectedIndex="{Binding BrowserTabControlSelectedIndex, Mode=TwoWay}"
                           ItemsSource="{Binding TabCollection}"
                           ContentTemplateSelector="{StaticResource selector}" />-->
        <TabControl x:Name="BrowserTabControl"
                    SelectedIndex="{Binding BrowserTabControlSelectedIndex, Mode=TwoWay}"
                    ItemsSource="{Binding TabCollection}"
                    ContentTemplateSelector="{StaticResource selector}" />
    </Grid>
</Window>