diff --git a/EduNetworkBuilder/NetworkBuilder.cs b/EduNetworkBuilder/NetworkBuilder.cs
index f2796dc..827639b 100644
--- a/EduNetworkBuilder/NetworkBuilder.cs
+++ b/EduNetworkBuilder/NetworkBuilder.cs
@@ -628,6 +628,7 @@ namespace EduNetworkBuilder
 
         private void pbNetworkView_Edit_Click(object sender, EventArgs e)
         {
+            if (ItemClickedOn == null) return;
             if (ItemClickedOn.GetNetType() == NetworkComponentType.microwave || ItemClickedOn.GetNetType() == NetworkComponentType.fluorescent)
                 return;
             if (ItemClickedOn != null)