How to get a TabControl to resize with other members inside of it

Question

I know that TabControl is not an item that automatically resizes, and that you can anchor it to a side and then set it to stretch and that may fix the problem, but are there any other ways to get the TabControl to expand to fullscreen when application is maximized? while also having all the properties expand and stay proportionate as well. And can this be done in the XAML rather than the code behind as I created everything within the XAML?

Bellow is a snip of the code for the MainWindow of the Application with the TabControl and one of the 5 TabItem's that it contains with all the other wpf properties that it includes. I'm trying to make it so that when maximized the whole application follows, Any advice?

XAML:

<Window x:Class="qaTrackingDatabase.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="QA Tracking DB Update Tool" Height="700.963" Width="868.283" Icon="rm12icon.ico" VerticalAlignment="Top">
<Grid Margin="0,0,-8,3">
    <Grid.Background>
        <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
            <GradientStop Color="#FFDFEDF7" Offset="0"/>
            <GradientStop Color="#FFDFECF7" Offset="1"/>
        </LinearGradientBrush>
    </Grid.Background>
    <TabControl  Name="myTabControl" Height="658" Width="858" Margin="0,10,0,0" SelectionChanged="TabControl_SelectionChanged" Background="#FFDFECF7" VerticalAlignment="Top">
        <TabItem x:Name="Branch" Header="Branch" Width="170" >
            <Grid HorizontalAlignment="Left">
                <RadioButton Name="Add" Content="Add" RenderTransformOrigin="0.488,0.454" Margin="25,28,618,548" Checked="Branch_RadioBtns_Checked"/>
                <RadioButton Name="Delete" Content="Delete" HorizontalAlignment="Left" Margin="25,99,0,0" VerticalAlignment="Top" Checked="Branch_RadioBtns_Checked" Height="49" Width="205"/>
                <TextBox Name="Add_Name_txtBox" IsEnabled="{Binding ElementName=Add, Path=IsChecked}" HorizontalAlignment="Left" Height="25" TextWrapping="Wrap" Text="Enter Name" VerticalAlignment="Top" Width="230" Margin="351,53,0,0" SpellCheck.IsEnabled="True" Background="White"/>
                <TextBlock TextDecorations="Underline" FontWeight="Bold" FontFamily="Levenim MT" Margin="250,57,509,336"> Branch Name:</TextBlock>
                <ComboBox Name="Dproduct_Combo" IsEnabled="{Binding ElementName=Delete, Path=IsChecked}" Text="Select" HorizontalAlignment="Left" Height="25" Margin="111,120,0,0" VerticalAlignment="Top" Width="119" IsReadOnly="True" SelectionChanged="Get_Dproduct_Branch"/>
                <TextBlock TextDecorations="Underline" FontWeight="Bold" FontFamily="Levenim MT" Margin="41,123,757,482"> Product:</TextBlock>
                <ComboBox Name="Aproduct_Combo" IsEnabled="{Binding ElementName=Add, Path=IsChecked}" Text="Select" HorizontalAlignment="Left" Height="25" Margin="111,53,0,0" VerticalAlignment="Top" Width="119"/>
                <TextBlock TextDecorations="Underline" FontWeight="Bold" FontFamily="Levenim MT" Margin="41,57,757,548"> Product:</TextBlock>
                <TextBlock TextDecorations="Underline" FontWeight="Bold" FontFamily="Levenim MT" Margin="250,123,509,478"> Select Branch:</TextBlock>
                <ComboBox Name="Dbranch_Combo" IsEnabled="{Binding ElementName=Delete, Path=IsChecked}" HorizontalAlignment="Left" Height="25" VerticalAlignment="Top" Width="119" IsReadOnly="True" Margin="351,119,0,0"/>
                <Button Content="Commit&#xD;&#xA;Changes" HorizontalAlignment="Left" VerticalAlignment="Top" Width="192" Margin="637,187,0,0" Height="49" FontFamily="Levenim MT" FontWeight="Bold" FontSize="16" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" Click="Branch_Commit_Changes"/>
            </Grid>
        </TabItem>

Answer 1

You have a fixed Height and Width and wonder why it does not resize?

Take the Margin off the Grid
Take the Height and Width off the TabControl