Correct. Have one column have more than one pane stacked on each other.
Meaning, I would want more panes in one window. This allows for more views of the same content while keeping content on each pane short (personally, it allow me to have more focus on things at hand, in any context, etc).
Also, allows to drag/drop items more ergonomically. Since you have more options to panes to, for example, panes as items statuses in Kanban boards.