Related: tdf#125266 set default dialog parent for SfxHelp

Change-Id: I375eeff07fd9c5fce4e037c5b6fd849570fb67c9
Reviewed-on: https://gerrit.libreoffice.org/72299
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

sfx2/source/appl/appserv.cxx

@@ -604,7 +604,7 @@ void SfxApplication::MiscExec_Impl( SfxRequest& rReq )
             Help* pHelp = Application::GetHelp();
             if ( pHelp )
             {
-                pHelp->Start(".uno:HelpIndex", static_cast<vcl::Window*>(nullptr)); // show start page
+                pHelp->Start(".uno:HelpIndex", Application::GetDefDialogParent()); // show start page
                 bDone = true;
             }
             break;