COLUMN MAPPING — port-row propagate & collapsed-port handle

Two changes. (1) The >> "propagate all from this port" moves out of the gutter and onto the input port row, after the column count: [ in-1  6  >> ]. (2) Fold a port (click its chevron) and its columns hide; every edge that touched them now converges on a single port handle next to the port row — visible only while collapsed. Try folding in-1 and out-1.