Small bugs

Selector/Selector.tsx:201-214 — identical at ComplexSelector.tsx:154-166 and MultiSelector.tsx:178-191 — tsx
// Rotation lives on the chevron glyph itself (passed through `xstyle`), not
// on the layout wrapper above, so the icon's `selector-indicator-icon` theme
// target and the open/closed transform sit on one element — a theme can
// restyle the mark and its rotation through a single selector. The wrapper
// keeps only layout. The status branch renders a different icon, so it never
// picks these up and needs no transition opt-out.
triggerIconRotation: {
  transitionProperty: 'transform',
  transitionDuration: durationVars['--duration-fast'],
  transitionTimingFunction: easeVars['--ease-standard'],
  transformOrigin: 'center',
},
triggerIconOpen: {
  transform: 'rotate(180deg)',
},

Lightbox/Lightbox.tsx:180-194, applied at :691 — tsx
image: {
  maxWidth: '100%',
  maxHeight: '100%',
  objectFit: 'contain',
  pointerEvents: 'none',
  transitionProperty: 'transform',
  transitionDuration: {
    default: '200ms',
    '@media (prefers-reduced-motion: reduce)': '0ms',
  },
  transitionTimingFunction: 'ease-out',
},
imageDragging: {
  transitionProperty: 'none',
},
​
// ...applied only while the pointer is down, Lightbox.tsx:691
isDragging && styles.imageDragging,

The class of bug, and the two ways out of it — tsx
// What the brief describes: a literal that has to be kept in sync by hand.
setTimeout(() => setMounted(false), 250);
​
// What removes the class of bug: the element says when it is done.
const panel = panelRef.current;
if (panel == null) {
  setMounted(false);
  return;
}
Promise.allSettled(panel.getAnimations().map(a => a.finished)).then(() =>
  setMounted(false),
);
​
// The transitionend form, for a single known property. Note the guard: a
// bubbling transitionend from a child would unmount the panel early, and a
// zero duration fires nothing at all — which is why --duration-instant
// cannot simply be 0.
panel.addEventListener('transitionend', event => {
  if (event.target === panel && event.propertyName === 'transform') {
    setMounted(false);
  }
});