Currently, if a piece is dragged such that its centre overlaps with the shape of another piece, it can stack. On the other hand, a piece sent to a location will only stack if coordinates match up perfectly.
This behaviour needs to be preserved as there may be modules based on it, but I would like to see an option in the send to trait to have behaviour like that of drag and drop - a piece sent to a location that overlaps another stackable piece in the same Layer will stack.
My use case is a piece in a lower Layer using Place Marker to generate pieces. By default, this doesn’t stack (the place on top of stack option only works when the parent piece and the placed piece are in the same Layer), but I use a key command to immediately send the placed piece to its current coordinates. This achieves a stack of placed pieces, unless a player has shifted one or more of the pieces by a few pixels in a previous interaction, then you get two or more overlapping stacks and counting pieces becomes tricky.