In a Delphi 12.1 VCL Application in Windows 11, I am trying to set up a TTaskDialog at design-time:

object TaskDialog2: TTaskDialog
  Buttons = <>
  Caption = 'Choose an Action'
  RadioButtons = <
    item
      Caption = 'Create a shortcut to this folder'
    end
    item
      Caption = 'Copy the folder and all its contents'
    end>
  Text = 'How do you want to insert the Folder?'
  Left = 676
  Top = 396
end

But there is no question mark choice for the MainIcon property.

I can load my own question mark ICO in CustomMainIcon at design-time. But how to show that CustomMainIcon?

The loaded CustomMainIcon is neither shown at design-time (with ‘Test Dialog’) nor at run-time (with TaskDialog2.Execute).