At the moment the App Bar does not appear in the Splash Portal preview, independently of your choice to publish the App Bar, or not.
This is a well-known limitation, and Cloud4Wi teams are fixing this issue.
In order to get a complete preview of the Splash Portal while you are creating it, you can simply create an external URL for the portal, as described in Publishing the Splash Portal on the Web.
By using this method you will be able to see the App Bar, if activated. At the moment the App Bar does not appear in the Splash Portal preview, independently from your choice to publish or not the App Bar.
This is a well-known limitation, and Cloud4Wi team will fix this issue as soon as possible.
In order to get a complete preview of the Splash Portal while you are creating it, you can simply create an external URL for the portal, as described in Publishing the Splash Portal on the Web.
By using this method you will be able to see the App Bar, if activated.