EXFO FTB-5230S Optical Spectrum Analyzer for FTB 200 v2 - Manual (Page 109)

Setting Up the Instrument in Drift Mode
OSA/OCA 103
Defining Preferences
5. Select whether you want to show or hide the empty channels from the
channel list in the Dashboard, Channel Graph, Channel Results and
Channel History tabs.
6. Select whether you want to show the horizontal markers or the
integrated power trace in the marker toolbar.