The inline word had to appear and then leave, which is two layout shifts around the control just pressed. On the button there are none: both labels share one grid cell, so it is sized by the wider of them and nothing moves when they swap.

The revert is CSS on the same four-second beat, because without script the label must still find its way back to Save. The announcement stays — sr-only, role=status — since a screen reader cannot read a button relabelling itself as an event. Reduced motion keeps the word and drops the movement. check-in: d28f1388fe user: dmestas tags: trunk