diff --git a/SharpDXTutorial/TutorialD1/Form1.cs b/SharpDXTutorial/TutorialD1/Form1.cs
index 914c7dd..1e9878e 100644
--- a/SharpDXTutorial/TutorialD1/Form1.cs
+++ b/SharpDXTutorial/TutorialD1/Form1.cs
@@ -132,7 +132,7 @@ private void Draw()
         private void Form1_Resize(object sender, EventArgs e)
         {
             //resize target
-            target.Resize(new Size2(this.ClientSize.Width, this.ClientSize.Height));
+            target?.Resize(new Size2(this.ClientSize.Width, this.ClientSize.Height));
         }
 
         private void Form1_FormClosing(object sender, FormClosingEventArgs e)