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known_issues.md · Known limitations · 2/5

Browse entries grouped by interface file. Expand an entry for declarations, usage and version boundaries.

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Entries retain declarations and sources. Runtime verification is recorded per entry; internal source candidates are not a promise of SDK delivery.

docs/known_issues.md
T-BUG-LOCAL-IMAGE-FILE-MAPPED-WHILE-CACHED
Known issue3.61.7C++

On Windows, once a local bitmap enters the image cache, overwriting the same file in place fails (for example, saving a new avatar or edit result back to the file currently displayed)

Verification scope

docs/known_issues.md:292

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T-BUG-LUA-CANVAS-FONT-SIZE-AS-WEIGHT
Known issue3.61.7C++

Lua Canvas mistakes 100-900px font sizes without a font weight for numeric weights and throws an exception

Verification scope

docs/known_issues.md:259

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T-BUG-LUA-MUTATIONOBSERVER-OBSERVE-REJECTS-ELEMENT
Known issue3.61.7C++

Lua MutationObserver:observe(element, ...) rejects elements with a type mismatch

Verification scope

docs/known_issues.md:400

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T-BUG-MARKER-CONTENT-NONE-SHOWS-MARKER
Known issue3.61.7C++

::marker{content:none} still paints and reserves space for the default marker

Verification scope

docs/known_issues.md:345

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T-BUG-MEASURE-SUBSTRING-UTF8-MID-CHAR-CRASH
Known issue3.61.7C++

measureSubstring crashes the process (0xC0000005) when byteEnd falls inside a multibyte UTF-8 character

Verification scope

docs/known_issues.md:267

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T-BUG-MULTILINE-INLINE-SCALAR-RECT-OTHER-READERS
Known issue3.61.7C++

The scalar rectangle of a multiline inline, combining first-fragment x with bounding width, is still treated as real occupied geometry by scrollIntoView, outline unions, and sticky positioning

Verification scope

docs/known_issues.md:130

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T-BUG-NEGATIVE-LEADING-ATOMIC-LINE-DROPS-STRUT-DESCENT
Known issue3.61.7C++

Lines rebuilt through the CSS line-box path, including negative half-leading or fallback-font cases, still lose the root strut descent when a baseline-aligned atomic box lowers the baseline

Verification scope

docs/known_issues.md:155

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T-BUG-NO-BACKEND-ATOMIC-GEOMETRY-ACCUMULATES-BOX-MODEL
Known issue3.61.7C++

Without a backend, nested percentage-sized atomic inline boxes repeatedly accumulate box edges on warm frames

Verification scope

docs/known_issues.md:173

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T-BUG-OOF-FLEX-GRID-STATIC-POSITION-CHROME-MATRIX
Known issue3.61.7C++

Auto static positions for fixed elements in flex and absolute/fixed elements in grid differ from Chrome

Verification scope

docs/known_issues.md:132

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T-BUG-OUTSIDE-MARKER-BESIDE-FLOAT-BOX-OFFSET
Known issue3.61.7C++

An outside list bullet beside a float differs from Chrome when the list item has padding/margin or establishes a BFC

Verification scope

docs/known_issues.md:215

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T-BUG-OVERFLOW-WORD-RESCUE-ALIGNMENT
Known issue3.61.7C++

Whole-word rescue widens the center/right/RTL alignment area when only some lines in a multiline paragraph overflow

Verification scope

docs/known_issues.md:182

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T-BUG-PERCENT-SIZE-RESOLVES-AGAINST-INLINE-PARENT
Known issue3.61.7C++

After an atomic box inside an inline element changes to percentage width, selective descent resolves it against the inline parent box width from the previous frame

Verification scope

docs/known_issues.md:122

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T-BUG-POSITIVE-LINE-CLAMP-SELECTIVE-STALE-TEXT-BASELINE
Known issue3.61.7C++

After text grows under positive line-clamp, a reused zero-width trailing text box retains its old baseline

Verification scope

docs/known_issues.md:218

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T-BUG-PSEUDO-STYLE-STALE-IN-STYLE-ONLY-ANIM-FRAMES
Known issue3.61.7C++

Style-only animation frames do not refresh ::before/::after styles; pseudo-elements retain old values while host color and other properties transition or animate

Verification scope

docs/known_issues.md:253

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T-BUG-RATIO-ONLY-IMAGE-SIZING-CONTRIBUTION
Known issue3.61.7C++

Ratio-only images without natural dimensions, including viewBox-only SVGs or dimensionless SVGs with an authored aspect-ratio, use raster sizes in shrink-to-fit, flex, and absolute positioning

Verification scope

docs/known_issues.md:135

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T-BUG-REFPTR-NEW-CREATE-LEAKS-NODES
Known issue3.61.7C++

create() for img, audio, video, lottie-player, and DocumentFragment retains one extra reference, so these nodes are never destroyed

Verification scope

docs/known_issues.md:284

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T-BUG-RELATIVE-INSET-PERCENT-NESTED-INLINE-BASIS
Known issue3.61.7C++

Percentage left/right on a relatively positioned inline nested in another inline resolve against the parent inline width instead of the containing block width of the nearest block container

Verification scope

docs/known_issues.md:164

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T-BUG-RETAINED-PARTIAL-LAYER-PROMOTION-STALE-AFTER-RELAYOUT
Known issue3.61.7C++

With retained surface, partial damage, and layer promotion all enabled, changing dir and laying out again a whole line leaves a region of pixels from the previous frame

Verification scope

docs/known_issues.md:250

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T-BUG-RETAINED-SURFACE-FRACTIONAL-DAMAGE-SHADOW-SEAM
Known issue3.61.7C++

With retained surface enabled (off by default), partial replay of fractional-coordinate explicit damage along the hollow edge of a box shadow differs from full-page rasterization by 30 pixels

Verification scope

docs/known_issues.md:370

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T-BUG-RTL-ATOMIC-BEFORE-HARD-BREAK-RUN-OFFSET
Known issue3.61.7C++

When a text run following an atomic inline box crosses a hard line break in an RTL paragraph, the atomic box shifts right and overlaps Hebrew text

Verification scope

docs/known_issues.md:169

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T-BUG-RTL-INLINE-EDGE-DETACHED-IN-LATIN-RUN
Known issue3.61.7C++

Inline-box edge placeholders next to Latin runs in RTL paragraphs follow their own bidi level, separating from box content or landing on the wrong side

Verification scope

docs/known_issues.md:153

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T-BUG-RTL-OVERFLOWING-ATOMIC-INLINE-START-EDGE
Known issue3.61.7C++

An atomic inline box wider than an RTL line sits at the left edge instead of overflowing from the end edge on the left

Verification scope

docs/known_issues.md:162

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T-BUG-SEGMENT-INLINE-ROOT-BOX-IS-PARAGRAPH-BOX
Known issue3.61.7C++

A separately laid-out inline root in segmented layout gets a paragraph box, including line-height and one solid multiline area, instead of an inline box

Verification scope

docs/known_issues.md:158

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T-BUG-SEGMENT-INLINE-ROOT-RTL-ALIGNMENT
Known issue3.61.7C++

In segmented RTL paragraph layout, a separately laid-out inline root shifts its entire glyph run rightward outside its box and overlaps following text

Verification scope

docs/known_issues.md:156

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T-BUG-SMALLER-INLINE-LOWERS-NUMERIC-LINE-HEIGHT-BASELINE
Known issue3.61.7C++

With numeric line-height, a smaller-font inline element places the line text and boxes about 2px lower than Chrome

Verification scope

docs/known_issues.md:163

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T-BUG-STEPS-JUMP-NONE-BOTH
Known issue3.61.7C++

steps(n, jump-none) and steps(n, jump-both) are treated as jump-end and jump-start

Verification scope

docs/known_issues.md:279

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T-BUG-STRETCHED-WRAPPED-COLUMN-FLEX-ITEM-IGNORES-BLOCK-SIZE
Known issue3.61.7C++

A wrapped column flex item stretched in a fixed-height single-line row flex container does not use its stretched height when wrapping into columns

Verification scope

docs/known_issues.md:63

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T-BUG-STYLE-CURRENTCOLOR-INHERIT-RESOLVED-EARLY
Known issue3.61.7C++

currentColor in border-*-color, text-decoration-color, column-rule-color, and row-rule-color is resolved during computed-value calculation, so a child using inherit receives the parent's color

Verification scope

docs/known_issues.md:276

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T-BUG-SVG-RENDERER-CONCURRENT-FIRST-CREATE
Known issue3.61.7C++

Four loader threads create the same SVG renderer concurrently without a lock during first SVG decoding, causing a data race

Verification scope

docs/known_issues.md:255

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T-BUG-TABLE-ABSPOS-CHILD-STATIC-POSITION-AFTER-CELL
Known issue3.61.7C++

An absolutely positioned child after cells in a display:table does not receive a static horizontal position after the cells

Verification scope

docs/known_issues.md:309

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T-BUG-TABLE-ALL-ROWS-COLLAPSED-DROPS-SPACING
Known issue3.61.7C++

When all table rows have visibility:collapse, KUI also removes the leading and trailing vertical border-spacing, making the table shorter than Chrome

Verification scope

docs/known_issues.md:312

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T-BUG-TABLE-ANONYMOUS-CELL-FAST-PATH-PERCENT-PADDING-SQUEEZE
Known issue3.61.7C++

A text-only display:table with percentage padding subtracts padding again from the content width, squeezing text into multiple lines

Verification scope

docs/known_issues.md:315

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T-BUG-TABLE-AS-FLEX-ITEM-GEOMETRY
Known issue3.61.7C++

Table geometry as a row flex item differs from Chrome: collapsed-border tables miss outer edges and separate-border tables gain extra border height

Verification scope

docs/known_issues.md:65

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T-BUG-TABLE-AUTO-LAYOUT-INLINE-BLOCK-COLUMN-WIDER-THAN-CHROME
Known issue3.61.7C++

An auto-layout table column containing several inline-block tags is much wider in KUI than in Chrome

Verification scope

docs/known_issues.md:85

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T-BUG-TABLE-CAPTION-INSIDE-TABLE-BORDER
Known issue3.61.7C++

A bordered or padded table places its caption inside its own border and padding, drawing the table border above the caption

Verification scope

docs/known_issues.md:98

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T-BUG-TABLE-CAPTION-WIDER-THAN-GRID-NO-STRETCH
Known issue3.61.7C++

Columns do not stretch when a caption is wider than the table grid, leaving the grid against one side of the table box: left in LTR and right in RTL

Verification scope

docs/known_issues.md:84

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T-BUG-TABLE-CELL-IB-SPLIT-ABSPOS-STATIC-X
Known issue3.61.7C++

In a positioned inline split by a block child inside a table cell, left:auto uses a static x after the split rather than before it

Verification scope

docs/known_issues.md:314

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T-BUG-TABLE-COL-PERCENT-WIDTH-IGNORES-SPACING
Known issue3.61.7C++

Percentage widths on col/colgroup use the whole table width without subtracting border-spacing, making columns wider than Chrome

Verification scope

docs/known_issues.md:99

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T-BUG-TABLE-COLLAPSED-COLUMN-DEFINITE-WIDTH-KEPT
Known issue3.61.7C++

A table with a collapsed column retains its fixed width and leaves blank space while Chrome shrinks the table

Verification scope

docs/known_issues.md:313

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T-BUG-TABLE-COLLAPSED-COLUMN-KEEPS-SPACING
Known issue3.61.7C++

A visibility:collapse column loses its track but leaves its border-spacing, making the table one spacing interval too wide

Verification scope

docs/known_issues.md:310

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T-BUG-TABLE-COLLAPSED-COLUMN-TIE-ORDER
Known issue3.61.7C++

With collapsed borders, equal-width, equal-style vertical borders of adjacent col/colgroup elements incorrectly choose the logically later border

Verification scope

docs/known_issues.md:311

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T-BUG-TABLE-FRACTIONAL-BORDER-SPACING-NOT-TRUNCATED
Known issue3.61.7C++

KUI retains fractional border-spacing while Chrome truncates it to integer pixels, making multicolumn tables progressively wider

Verification scope

docs/known_issues.md:100

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T-BUG-TABLE-INLINE-CHILD-CHROME-GEOMETRY-L6
Known issue3.61.7C++

An inline-block child of a fixed-width display:table is stretched too wide, and table height differs from Chrome when a later static block enters flow

Verification scope

docs/known_issues.md:101

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T-BUG-TABLE-ROWSPAN-EXCESS-IGNORES-SPACING
Known issue3.61.7C++

When a spanning cell is taller than the sum of its rows, excess-height distribution omits the crossed vertical border-spacing and makes the table too tall

Verification scope

docs/known_issues.md:97

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T-BUG-TEXT-OVERFLOW-DECORATION-UNDER-ELLIPSIS
Known issue3.61.7C++

Text decoration on text truncated by text-overflow continues beneath the ellipsis

Verification scope

docs/known_issues.md:191

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T-BUG-TEXT-OVERFLOW-NO-ELLIPSIS-WITH-MARKER-OR-ABSPOS
Known issue3.61.7C++

Nowrap text-overflow has no ellipsis when the line contains an inside list marker or an out-of-flow child

Verification scope

docs/known_issues.md:195

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T-BUG-TEXT-OVERFLOW-RESCUE-REPACKS-LINES
Known issue3.61.7C++

With a word that does not fit, a soft-wrapped paragraph declaring text-overflow has one fewer line than the same paragraph without it

Verification scope

docs/known_issues.md:188

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T-BUG-TRANSLUCENT-ROUNDED-OVERFLOW-EDGE-CONFLATION
Known issue3.61.7C++

A translucent rounded box with overflow:hidden (such as a frosted-glass dialog) shows a faint light edge along children at fractional positions during entrance scaling, translation, or centering

Verification scope

docs/known_issues.md:257

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T-BUG-VERTICAL-TEXT-SHADOW-NOT-ROTATED
Known issue3.61.7C++

Vertical text (writing-mode:vertical-rl and similar modes) draws text-shadow horizontally without rotating it with the text

Verification scope

docs/known_issues.md:251

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T-BUG-VISIBILITY-COLLAPSE-NON-TABLE-PRUNES-VISIBLE-DESCENDANTS
Known issue3.61.7C++

visibility:collapse on non-table elements prunes the entire subtree: explicitly visible descendants are neither painted nor hit-tested, while Chrome treats it as hidden

Verification scope

docs/known_issues.md:372

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T-BUG-WEBKIT-LINE-CLAMP-BLOCK-CHILDREN-NOT-CLAMPED
Known issue3.61.7C++

-webkit-line-clamp on -webkit-box does not count lines across block children

Verification scope

docs/known_issues.md:193

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T-DEBT-ABSPOS-INLINE-CB-MULTILINE-PREV-TEXTBOX-APPROXIMATE
Known issue3.61.7C++

The previous-sibling fallback for an inline containing block still gives an inaccurate origin when per-line fragments are disabled and the previous text box spans multiple lines

Verification scope

docs/known_issues.md:175

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T-DEBT-ADVEX-TOOLING-WINDOWS-HARDCODED-PATHS
Known issue3.61.7C++

Remove hardcoded Windows paths from the advanced-example toolchain

Verification scope

docs/known_issues.md:383

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T-DEBT-BLOCKIFY-INLINE-BLOCK
Known issue3.61.7C++

Floating or absolutely positioned display:inline-block elements are not blockified; computed display remains inline-block

Verification scope

docs/known_issues.md:322

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T-DEBT-BROWSERCOMPAT-CONTROL-BASELINE-CALIBRATION
Known issue3.61.7C++

Temporary BrowserCompat compensation for form-control baselines and listboxes

Verification scope

docs/known_issues.md:141

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T-DEBT-CLIPPED-REPLAY-DEGENERATE-INK-BOUNDS
Known issue3.61.7C++

Review shared ink-bound pre-culling behavior for degenerate borders, thick wavy lines, and transformed glyphs

Verification scope

docs/known_issues.md:245

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T-DEBT-CLIPPED-REPLAY-WINDOW-UNMODELED-LISTS
Known issue3.61.7C++

Clipped replay cannot construct raster windows for lists containing clip-path, masks, backdrop-filter, 3D matrices, or non-blur filters; animation-only tiles intersecting curved primitives still differ by several levels from full-image rendering

Verification scope

docs/known_issues.md:256

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T-DEBT-CROSSPLATFORM-FONT-GENERIC-MAPPING-DUPLICATED
Known issue3.61.7C++

Consolidate cross-platform generic font mappings

Verification scope

docs/known_issues.md:373

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T-DEBT-CSS-COUNTER-STYLES-WPT-CATALOG
Known issue3.61.7C++

Implement the CSS Counter Styles capabilities actually used by WPT in stages

Verification scope

docs/known_issues.md:271

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T-DEBT-CSS-VAR-BORDER-WIDTH-PERCENT-VALIDATION
Known issue3.61.7C++

border-width does not fall back according to property syntax when var substitution introduces an expression containing percentages

Verification scope

docs/known_issues.md:275

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T-DEBT-CSS-ZOOM-END-TO-END
Known issue3.61.7C++

End-to-end CSS zoom semantics for computed style, layout space, paint coordinates, scroll overflow, and hit testing

Verification scope

docs/known_issues.md:117

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T-DEBT-CSSOM-BORDER-IMAGE-OUTSET-AND-GRADIENT-SERIALIZATION
Known issue3.61.7C++

getComputedStyle for border-image-*: nonzero outset values and gradient/filter() sources still return empty strings

Verification scope

docs/known_issues.md:282

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T-DEBT-CSSOM-RESOLVED-VALUE-PARITY
Known issue3.61.7C++

Some categories of element used values and computed forms remain unfinished in the CSSOM reading layer

Verification scope

docs/known_issues.md:273

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T-DEBT-CSSOM-RESOLVED-VALUE-RUNTIME-FOLD-BOXES
Known issue3.61.7C++

P2: runtime fold boxes lack independent CSS used-value data, so reads temporarily fall back to computed values

Verification scope

docs/known_issues.md:274

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T-DEBT-DECORATING-BOX-BASELINE-RESIDUAL
Known issue3.61.7C++

Two approximations in the decorating-box baseline

Verification scope

docs/known_issues.md:327

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T-DEBT-DECORATION-SKIP-INK-CHROME-PARITY
Known issue3.61.7C++

The gaps produced by text-decoration-skip-ink:auto differ from Chrome

Verification scope

docs/known_issues.md:365

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T-DEBT-DECORATION-STYLE-SHAPE-CHROME-PARITY
Known issue3.61.7C++

Wavy-line shapes and dashed-line endpoint antialiasing differ from Chrome

Verification scope

docs/known_issues.md:366

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T-DEBT-DETAILS-INLINE-CONTENT-SLOT-IB-SPLIT
Known issue3.61.7C++

IB splitting, intrinsic width, and wrapping for inline details/summary and anonymous ::details-content block/contents slots

Verification scope

docs/known_issues.md:212

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T-DEBT-DETAILS-SUMMARY-MARKER-INLINE-LAYOUT
Known issue3.61.7C++

Details/summary markers, anonymous boxes, inline display, and inherited list/decoration styles

Verification scope

docs/known_issues.md:211

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T-DEBT-DEVTOOLS-COUNTER-FIELD-CONTRACT
Known issue3.61.7C++

Performance.renderStats and repaintRects field names and semantics lack an authoritative list

Verification scope

docs/known_issues.md:289

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T-DEBT-DEVTOOLS-MOUSE-INJECTION-FORCES-FULL-FRAME
Known issue3.61.7C++

DevTools-injected mouse events force a full frame each time, unlike real mouse input, inflating frame counts and style work measured during animations

Verification scope

docs/known_issues.md:362

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T-DEBT-DEVTOOLS-PERF-CHART-Y-AXIS
Known issue3.61.7C++

The Frame Time History vertical axis cannot scale below 20ms when the entire time window is below that level

Verification scope

docs/known_issues.md:389

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T-DEBT-DEVTOOLS-UI-INL-MANUAL-REGEN
Known issue3.61.7C++

devtools_ui.inl still requires a manual generation step

Verification scope

docs/known_issues.md:390

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T-DEBT-EQUIVALENCE-CHECK-CONSUMER-ACCESS
Known issue3.61.7C++

Consumers cannot use the incremental-layout equivalence self-check (KUI_DEBUG_LAYOUT_EQUIVALENCE_CHECK)

Verification scope

docs/known_issues.md:290

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T-DEBT-EXT3D-LINUX-REQUIRES-LIBCXX-TOOLCHAIN
Known issue3.61.7C++

Reduce the hard dependency of ext3d on the libc++ toolchain on Linux

Verification scope

docs/known_issues.md:386

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T-DEBT-FIELDSET-LEGEND-MINIMUM-OCCUPANCY
Known issue3.61.7C++

The legend overlap can shrink to zero, whereas Chromium does not shrink it below the block-start border

Verification scope

docs/known_issues.md:140

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T-DEBT-FIELDSET-LEGEND-SHRINK-TO-FIT
Known issue3.61.7C++

A rendered legend stretches to the fieldset content width instead of shrinking to its own content width

Verification scope

docs/known_issues.md:139

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T-DEBT-FIRST-LINE-FRACTIONAL-OPACITY-COMPOSITING
Known issue3.61.7C++

Fragment-level compositing of ::first-line with 0 < opacity < 1

Verification scope

docs/known_issues.md:248

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T-DEBT-FIXED-TABLE-INTRINSIC-KEYWORD-PERCENT-ROWS
Known issue3.61.7C++

Percentage handling for fixed-table min-content/fit-content differs from subsequent spanning-cell intrinsic contributions

Verification scope

docs/known_issues.md:92

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T-DEBT-FIXED-TABLE-ZERO-TRACK-CELL-FRAMING
Known issue3.61.7C++

Zero-width cells after fixed percentage tracks exhaust the width budget include extra padding in their frames

Verification scope

docs/known_issues.md:91

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