The Config tab's footer sat mid-panel with further rows drawing below the
window's bottom edge. Live-DAT measured: the mounted tab-host root is
authored 300x362 (retail's real default window size), but the Config page
slot underneath keeps its own larger design geometry (298x575 against a
300x600 canvas) until retail's real four-edge UiLayoutPolicy
(UIElement::UpdateForParentSizeChange @0x00462640) shrinks it on the first
ApplyAnchor pass -- verified stable, this part already worked.
The actual bug: UiTemplateListBox.Viewport (the UiScrollablePanel that
hosts + clips every row) is a programmatic C# element seeded at Bind time,
BEFORE the tree's first draw frame -- before the ListBox has ever shrunk.
Its legacy anchor baseline is captured lazily on its own first ApplyAnchor
call, which lands AFTER the ListBox has already shrunk earlier in that same
frame (parent-before-child draw order). That capture measures a negative
bottom margin the stretch math preserves forever: the viewport stayed
locked at its original 560px design height, clipping rows to a bound
retail never actually gave the window on screen.
Fix: force the viewport's anchor capture to happen immediately after
seeding it, while its Width/Height still exactly equal a zero-margin
baseline against the CURRENT (pre-shrink) parent, instead of lazily on the
first draw frame against an already-shrunk parent. This is #372's sequel --
#372 fixed the 0x0 collapse case; this is the "ListBox itself later
shrinks" case #372's own fixture never exercised.
Three new tests (UiTemplateListBoxViewportTests using the live-DAT-measured
298x575/276x560 numbers, plus two ConfigOptionsPageControllerTests against
the real production Bind path and the committed host fixture) all fail
pre-fix, confirmed by temporarily reverting the change. Scoped to
UiTemplateListBox's own viewport; UiScrollablePanel/ApplyAnchor/
ComputeAnchoredRect are untouched, so chat's transcript scrolling and every
other UiScrollablePanel/UiItemList consumer are unaffected.
fix#412
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
ROOT CAUSE (proven, not guessed): the lazily-created row viewport was
constructed 0x0 with Left|Top|Right|Bottom fill-anchors. Its first
ApplyAnchor captured mR = parentW - (0+0) = parentW, so
ComputeAnchoredRect's l&&r branch (w = parentW - mR - mL) kept it 0x0
forever. A 0-tall viewport makes UiScrollablePanel.LayoutScrollableChildren
cull every row, so Character/Chat/Config rendered blank while Gameplay
(no viewport — authored static children sized at Build) worked. This is
the exact Gameplay-vs-rest split the user's first connected gate found.
FIX: seed the viewport to the ListBox's current extent at creation, so the
fill-anchor baseline is mR = parentW - parentW = 0 and the viewport tracks
the parent. The ListBox is a static dat child sized at Build, so its extent
is authored by the time the viewport is lazily created during Bind.
Dormancy preserved — the viewport is still created only on the first row.
Reproduced RED then GREEN by UiTemplateListBoxViewportTests (viewport fills;
rows stay visible after the anchor+cull layout pass) — the layout path the
whole fixture conformance suite structurally never drove, which is why
every OP2-OP6 test was green over a live-only blank-tab failure. Full
Release suite 13,131 / 4 skips / 0 failed.
Still owed (NOT fixed here, no evidence yet): the 'only Exit Game worked'
Gameplay-buttons observation needs a re-gate (two buttons are correctly
INERT; the other four have dialog/chat effects that may have gone
unnoticed); and the 13 ID_ChatOption_TextFilter_* labels fail to resolve
(blank captions, behaviour unaffected). See #372.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
