kmpdfkit_demo/Demo/Examples/Compdfkit_Tools/Edit/PDFContentEditControl.xaml

<UserControl x:Class="Compdfkit_Tools.Edit.PDFContentEditControl"
             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:Compdfkit_Tools.Edit"
             mc:Ignorable="d" 
             d:DesignHeight="800" d:DesignWidth="300"
              Background="#FAFCFF">
    <Grid>
        <TextBlock x:Name="EmptyMessage" Text="The property panel is empty." VerticalAlignment="Center" HorizontalAlignment="Center"></TextBlock>
        <Border x:Name="ContentEditContainer"></Border>
    </Grid>
</UserControl>