What is shown in the clusters tab?

The clusters tab is intended specifically to be used for molecular design. In the clusters tab, each cluster is the same landscape you see in the molecules tab but shown as tiles colored by the average bioactivity of all of the molecules in the cluster. When selected, each tile displays an image of the most representative structure in the cluster. This gives you a quick view of the contents of the cluster. 

Selection also shows you a breakdown of bioactivity and assignee for the cluster, as well as compound structures for all molecules in the cluster and details on bioactivity for each. The selection will display the centroid molecule, with the most common substructure highlighted.