Added all the controls needed to update the core item properties on the main form.

InventoryTest/Form1.cs

@@ -31,7 +31,7 @@ namespace InventoryTest
         private void ShowCategoryManagerForm(object sender, EventArgs e)
         {
             var form = new CategoryManager(ConnectionString);
-            form.Show();
+            form.ShowDialog();
         }
     }
 }