Hosting a Windows Control in WPF Application

I am very new with WPF. I am using a panel from winforms control using the reference WindowsFormsHost. Panel is shown over the controls of wpf controls. When I am scroll down the page panel moves over the controls of wpf controls.

Here is the Xaml source code

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:wf="clr-namespace:System.Windows.Forms;assembly=System.Windows.Forms"
xmlns:af="clr-namespace:System.Windows.Forms.Integration;assembly=WindowsFormsIntegration"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300"
Title="Page1">

Output

Thank you....