In the recorded radio screen, the icons for channels are not shown. Compare this to the recorded TV screen in the list views, where channel thumbs are shown.

http://forum.team-mediaportal.com/mediaportal-releases-315/issues-recorded-radio-please-confirm-92196/

As an additional comment, in the forum thread above, there are issues with overlays for recorded radio, including a difference between the behaviour in singleseat and multiseat. In singleseat, the overlays are shown for recorded radio, but the thumbs are not shown in the overlay as they are for live radio. Perhaps this is a related issue?