addon.arrange.groupOverlapping groups the selected top-level objects
whose visual bounds overlap or touch, chains included (union-find over a
sweep along x, at most 20000 objects), only within one layer or group.
Each group takes its frontmost member's stacking place; one undo step,
all groups made in one pass over the tree. Menu item, tests, sweep case,
catalog rows and docs.
bflatastic
69985f4998