DX Cluster - DX Spots Options
DX Cluster spots are shown in different colors depending on whether you have worked a station or not and other options. An incoming spot is always checked against your log. The log search is based on the Band Plan and whether you want just the band checked against the log or against band and mode. Check the Search Log option above accordingly.
DX spots are removed automatically from the DX Spots Tab after a certain lifetime that can be set here in minutes. The spots are not automatically cleared if you set the lifetime to 0.