diff --git a/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/ChildWindow/Implementation/ChildWindow.cs b/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/ChildWindow/Implementation/ChildWindow.cs
index c5b839c8..13b6b1ad 100644
--- a/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/ChildWindow/Implementation/ChildWindow.cs
+++ b/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/ChildWindow/Implementation/ChildWindow.cs
@@ -41,6 +41,9 @@ namespace Microsoft.Windows.Controls
 
         public ChildWindow()
         {
+            if (DesignerProperties.GetIsInDesignMode(this))
+                WindowState = Controls.WindowState.Open;
+
             IsVisibleChanged += ChildWindow_IsVisibleChanged;
 
             _modalLayer.Fill = OverlayBrush;