Can tdiQuestion be added to TaskDialog.MainIcon?

The reason for the lack of a tdiQuestion option for the MainIcon property is that TaskDialog is a wrapper around the new TaskDialogIndirect () function from Vista, and the TASKDIALOGCONFIG used by this function does not contain TD_ERROR_ICON in the pszMainIcon field.

If you read the Windows User Interaction Guides , specifically the Confirmations section , you will notice that the Question Icon has been deprecated for a long time, so it is fitting that the task dialog no longer provides it, even though it is still supported for the MessageBox () from backward compatibility considerations.

You will notice that a task dialog with "Do you want to save changes to Untitled?" the question in the documentation above has no icon, so you should probably be fine too.