The outline was the last piece with nothing to morph against, so it could only fade in place while everything around it moved. The expanded grid draws no outline by design — once the cells carry real event bars it is one mark too many — which left it partnerless. Same answer as the multi-day dots: give it an invisible stand-in over the same cell in the expanded grid. It draws nothing and exists only to be the other end of the morph, so the outline now rides its cell between the two layouts. Tagged only while it is the selected day. Tagged unconditionally it would put a key on all 42 cells against the single partner on offer, and the other 41 would fly in from the layout origin — the failure the dots just had. The stand-in carries the same padding as the outline's own bounds, or it would arrive at the wrong size, and it sits in its own layer rather than inside the cell pill, which is itself tagged and would make it travel twice. MonthGrid takes `selected` again, but for an anchor rather than a mark; the other styles pass nothing and compose no extra layer at all. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>