prs/prs.desktop/Panels/Suppliers/SupplierBillPanel.xaml

<UserControl x:Class="PRSDesktop.SupplierBillPanel"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:local="clr-namespace:PRSDesktop"
             xmlns:dynamicGrid="clr-namespace:InABox.DynamicGrid;assembly=InABox.Wpf"
             mc:Ignorable="d"
             d:DesignHeight="300" d:DesignWidth="1000">
    <dynamicGrid:DynamicSplitPanel View="Combined" AnchorWidth="500">
        
        <dynamicGrid:DynamicSplitPanel.Header>
            <Border BorderBrush="Gray" BorderThickness="0.75" Background="WhiteSmoke">
                <Label Content="Bills" VerticalContentAlignment="Center" HorizontalContentAlignment="Center"/>
            </Border>
        </dynamicGrid:DynamicSplitPanel.Header>
        
        <dynamicGrid:DynamicSplitPanel.Master>
            <local:SupplierBills x:Name="Bills" OnSelectItem="Bills_OnOnSelectItem"/>
        </dynamicGrid:DynamicSplitPanel.Master>
        
        <dynamicGrid:DynamicSplitPanel.Detail>
            <dynamicGrid:EmbeddedDynamicEditorForm x:Name="Bill" OnOK="Bill_OnOnOK" OnCancel="Bill_OnOnCancel" Margin="-5"/>
        </dynamicGrid:DynamicSplitPanel.Detail>
        
    </dynamicGrid:DynamicSplitPanel>
</UserControl>