+If you provide a window, it will be used by some help controller classes, such as
+wxCHMHelpController, wxWinHelpController and wxHtmlHelpController, as the
+parent for the help window instead of the value of \helpref{wxApp::GetTopWindow}{wxappgettopwindow}. You can also change the parent window later with
+\helpref{wxHelpController::SetParentWindow}{wxhelpcontrollersetparentwindow}.
+