Added not null operators

I18N Commander/UI WinForms/Components/Setting.cs

@@ -212,7 +212,7 @@ public sealed partial class Setting : UserControl
                     };
 
                     // Update the explanation text. Therefore, we need to get the setting object through the chain of parents:
-                    var setting = (Setting) ((Control) sender).Parent.Parent.Parent;
+                    var setting = (Setting) (((Control) sender!)!).Parent.Parent.Parent;
                     setting.UpdateExplanation();
                 };