Retail authors TWO distinct UIElement_Scrollbar thumb shapes.
DatWidgetFactory.BuildScrollbar's existing vertical-thumb detection was
built against chat's own scrollbar (0x10000012) — a 3-slice composite
where the thumb child carries no media of its own and three Type-3
grandchildren supply the top-cap/middle/bottom-cap sprites. The chargen
Skills listbox scrollbar (0x100003f8), Summary's OVERVIEW listbox
scrollbar (0x10000401), the Summary how-to box's scrollbar (0x100002e7),
and the shade slider (0x10000321) all instead author a SIMPLE
single-sprite thumb: the same structural child (Type 1, id 1, not the
inc/dec button) carries its OWN direct media and has ZERO children — the
3-slice-only search found nothing for this shape, so every Thumb*Sprite
stayed 0 regardless of overflow.
Fixed by falling back to the thumb's own DefaultImage when the slice
search finds nothing — additive; a thumb WITH real slice children (chat)
is unaffected. This one fix covers R3-4's three listbox thumbs, R3-7, and
— as a natural consequence of the same structural shape — the shade-slider
indicator half of R3-5(c); no separate fix was needed there.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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