make new option type for internal purposes

Core/Handler/SettingsHandler.cs

@@ -159,6 +159,12 @@ public class SettingsHandler : CommonHandler
                 button.Text += $" ({currentChoice.ShortName})";
                 break;
             }
+
+            case OptionType.Hidden:
+            {
+                button = null;
+                break;
+            }
         }
 
         return button;
@@ -185,6 +191,7 @@ public class SettingsHandler : CommonHandler
     {
         var keyboardLayout = _options.ToAsyncEnumerable()
             .SelectAwait(async x => await GetKeyboardButton(x))
+            .Where(x => x != null) // for OptionType.Hidden
             .ToEnumerable()
             .Chunk(2);
 

Core/Options/OptionType.cs

@@ -3,5 +3,6 @@
 public enum OptionType
 {
     OnOff,
-    Select
+    Select,
+    Hidden
 }