stacked-tree is a pane that displays a tree of items in a "stacked" drawing, where each item has an associated value and child items that represent a fraction of that value. Each item is displayed as a colored rectangle whose width corresponds to the value. Child items are displayed below the item to make a stack of rectangles.
The Stacked Tree tab of the Profiler tool in the LispWorks IDE is a situation where a stacked tree is useful.
CAPI User Guide and Reference Manual (Windows version) - 3 Aug 2017