Since a recent update to 10.5.1 (Win8 64bit) I can't get the "dual horizontal" display. The only proposed predefined style which is proposed is "Commander" ==> Dual Horizontal,Dual Vertical,Explorer, Filmstrip,Images, Metadata and Single are GONE! As shown below in the screeen capture.
Help! I've been using Dual Horizontal for years and can't do without it (never had a problem with Opus either)