Update see also links (#7636)

Author: gewarren

xml/System.Windows.Controls/Panel.xml

@@ -44,9 +44,7 @@
   
  <xref:System.Windows.Controls.Panel> elements do not receive mouse or stylus events if a <xref:System.Windows.Controls.Panel.Background%2A> is not defined. If you need to handle mouse or stylus events but do not want a background for your <xref:System.Windows.Controls.Panel>, use <xref:System.Windows.Media.Brushes.Transparent%2A>.  
   
- Panel elements do not receive focus by default. To compel a panel element to receive focus, set the <xref:System.Windows.UIElement.Focusable%2A> property to `true`.  
-  
-   
+ Panel elements do not receive focus by default. To compel a panel element to receive focus, set the <xref:System.Windows.UIElement.Focusable%2A> property to `true`.
   
 ## Examples  
  The following example shows how to use the <xref:System.Windows.Controls.Panel.Children%2A> property to add two <xref:System.Windows.Controls.Button> objects to a <xref:System.Windows.Controls.StackPanel>.  
@@ -57,8 +55,8 @@
   
  ]]></format>
     </remarks>
-    <related type="ExternalDocumentation" href="https://go.microsoft.com/fwlink/?LinkID=159979">Create a Custom Content-Wrapping Panel Sample</related>
-    <related type="ExternalDocumentation" href="https://go.microsoft.com/fwlink/?LinkID=160053">WPF Controls Gallery Sample</related>
+    <related type="Article" href="/dotnet/desktop/wpf/controls/how-to-create-a-custom-panel-element">How to: Create a Custom Panel Element</related>
+    <related type="ExternalDocumentation" href="https://github.com/Microsoft/WPF-Samples/tree/master/Getting%20Started/ControlsAndLayout">WPF Controls Gallery Sample</related>
   </Docs>
   <Members>
     <Member MemberName=".ctor">