Going back to Rhino 4 or 5, a select set of commands supported history for subobjects in a Block. I believe those commands looked at a block as an array of objects and stored an index number to the parent. When you edited a block, the sort order for the array changed, essentially breaking history. A command’s history replay would pull the wrong element, i.e. _Offset would begin offsetting the wrong crv.
This changed sometime in the past year. I looked through all the service release notes for v7 and didn’t see anything about blocks changing. Does anyone know when this happened? I’d like to know what else has changed.
And one for the wishlist: sub-object selection is a bit wonky. Is there any way it can work like selecting an object in a _Group? At least when a command is asking for input.