fix(studio): resolve 8 confirmed adversarial-review findings across the flat-inspector stack

Fixes issues raised in the Deepwork re-review of #2120-#2190 that weren't
covered by #2225's earlier fix pass:

- useColorGradingController: reset grading/compare/mediaMetadata state (and
  cancel pending persist/status timers) when selection changes to a
  different element — this hook is called unconditionally on every render
  (unlike legacy ColorGradingSection, remounted via a selectionIdentityKey
  React key), so switching selection reused the previous element's state.
- useColorGradingController: stop permanently caching a non-OK
  /media/metadata response as null — a transient server error poisoned the
  HDR banner for that asset for the whole page lifetime.
- FlatSelectRow: preserve a valid authored value outside the preset list
  (e.g. mix-blend-mode: difference, an arbitrary object-position) instead of
  silently misrepresenting it as the first preset — touching the control
  would overwrite real persisted state.
- FlatSlider: the throttled trailing commit now reads onCommit through a
  ref updated every render instead of closing over it at schedule time — a
  caller whose onCommit spreads other current state (Grade's per-detail
  commits) could otherwise have a delayed commit revert whatever the user
  changed on a different control in the same 40ms window.
- FlatSlider: flush a still-queued trailing commit on unmount instead of
  dropping it, and disable the reset button when the slider itself is
  disabled.
- FlatSlider: add touch-action: none to the track so touch drags don't
  compete with page scroll.
- FlatColorGradingAccessory: clean up the compare-hold's window listeners
  on unmount, not only on release — switching selection mid-hold used to
  leak them.
- Align (flat Text): re-clicking the option already visually active for a
  logical start/end value no longer rewrites it to the physical left/right,
  preserving RTL semantics.
- FlatSegmentedRow: give every option an accessible name and aria-pressed
  state — two visually-identical glyph buttons (upright/italic "A") had no
  way to be told apart by assistive tech.
- PropertyPanelFlat: the panel body falls back to its own scroll when the
  collapsed group headers alone exceed the available height, so groups
  can't become permanently unreachable in a short pane.

New regression tests for all of the above; full studio suite at the known
pre-existing baseline (55 failures unrelated to this stack).

packages/studio/src/components/editor/PropertyPanelFlat.tsx

@@ -516,7 +516,7 @@ export function PropertyPanelFlat({
         onUngroup={onUngroup}
         showUngroup={Boolean(onUngroup && element.dataAttributes["hf-group"] != null)}
       />
-      <div data-flat-panel-body="true" className="flex min-h-0 flex-1 flex-col overflow-hidden">
+      <div data-flat-panel-body="true" className="flex min-h-0 flex-1 flex-col overflow-y-auto">
         {beforeOpen.map((g) => (
           <FlatGroupHeader
             key={g.id}

packages/studio/src/components/editor/propertyPanelFlatColorGradingSection.tsx

@@ -1,4 +1,4 @@
-import { useMemo, useRef, useState } from "react";
+import { useEffect, useMemo, useRef, useState } from "react";
 import {
   HF_COLOR_GRADING_PRESETS,
   isHfColorGradingActive,
@@ -32,6 +32,18 @@ export function FlatColorGradingAccessory({
 }) {
   const { grading, compareEnabled, runtimeStatus, commitCompare, resetGrading } = state;
   const gradingActive = isHfColorGradingActive(grading);
+  // Tracks the active hold's cleanup so it can be torn down on unmount too —
+  // without this, switching selection away mid-hold (unmounting this
+  // accessory) leaves the pointerup/pointercancel/blur listeners registered
+  // on `window` forever, each holding a closure over the old commitCompare.
+  const releaseRef = useRef<(() => void) | null>(null);
+  useEffect(
+    () => () => {
+      releaseRef.current?.();
+      releaseRef.current = null;
+    },
+    [],
+  );
 
   return (
     <span className="flex items-center gap-2.5">
@@ -50,7 +62,9 @@ export function FlatColorGradingAccessory({
             window.removeEventListener("pointerup", release);
             window.removeEventListener("pointercancel", release);
             window.removeEventListener("blur", release);
+            releaseRef.current = null;
           };
+          releaseRef.current = release;
           window.addEventListener("pointerup", release);
           window.addEventListener("pointercancel", release);
           window.addEventListener("blur", release);

packages/studio/src/components/editor/propertyPanelFlatLayoutSection.tsx

@@ -203,8 +203,8 @@ export function LayoutFlexBlock({
       <FlatSegmentedRow
         label="Direction"
         options={[
-          { key: "row", node: "→ Row", active: direction === "row" },
-          { key: "column", node: "Column", active: direction === "column" },
+          { key: "row", node: "→ Row", label: "Row", active: direction === "row" },
+          { key: "column", node: "Column", label: "Column", active: direction === "column" },
         ]}
         disabled={disabled}
         onChange={(next) => void onSetStyle("flex-direction", next)}

packages/studio/src/components/editor/propertyPanelFlatMaskInsetRows.tsx

@@ -0,0 +1,102 @@
+import {
+  buildInsetClipPathSides,
+  buildInsetClipPathValue,
+  formatNumericValue,
+  formatPxMetricValue,
+  getClipPathInsetPx,
+  inferClipPathPreset,
+  parseInsetClipPathSides,
+  parsePxMetricValue,
+  type ClipPathInsetSides,
+} from "./propertyPanelHelpers";
+import { FlatSlider } from "./propertyPanelFlatPrimitives";
+import { MetricField } from "./propertyPanelPrimitives";
+
+/* ------------------------------------------------------------------ */
+/*  Flat Mask inset — uniform slider + per-side fields                 */
+/*  (split out of propertyPanelFlatStyleSections.tsx to stay under the */
+/*  600-line file-size gate)                                           */
+/* ------------------------------------------------------------------ */
+
+export function FlatMaskInsetRows({
+  clipPathValue,
+  radiusValue,
+  disabled,
+  onSetStyle,
+}: {
+  clipPathValue: string;
+  radiusValue: number;
+  disabled: boolean;
+  onSetStyle: (prop: string, value: string) => void | Promise<void>;
+}) {
+  const clipPathPreset = inferClipPathPreset(clipPathValue);
+  const parsedClipInsets = parseInsetClipPathSides(clipPathValue);
+  const clipInsetValue = getClipPathInsetPx(clipPathValue);
+  const clipInsetSides = parsedClipInsets ?? {
+    top: clipInsetValue,
+    right: clipInsetValue,
+    bottom: clipInsetValue,
+    left: clipInsetValue,
+    radius: radiusValue,
+  };
+  const showClipInsetSides = clipPathPreset === "inset" || parsedClipInsets != null;
+
+  const commitClipInsetSide = (side: keyof ClipPathInsetSides, nextValue: string) => {
+    const next = parsePxMetricValue(nextValue);
+    if (next == null) return;
+    const sides: ClipPathInsetSides = {
+      top: clipInsetSides.top,
+      right: clipInsetSides.right,
+      bottom: clipInsetSides.bottom,
+      left: clipInsetSides.left,
+    };
+    sides[side] = next;
+    void onSetStyle("clip-path", buildInsetClipPathSides(sides, clipInsetSides.radius));
+  };
+
+  return (
+    <>
+      <FlatSlider
+        label="Mask inset"
+        value={clipInsetValue}
+        min={0}
+        max={Math.max(120, Math.ceil(clipInsetValue))}
+        step={1}
+        tier={clipInsetValue > 0 ? "explicitCustom" : "default"}
+        displayValue={`${formatNumericValue(clipInsetValue)}px`}
+        disabled={disabled}
+        onCommit={(next) =>
+          void onSetStyle("clip-path", buildInsetClipPathValue(next, radiusValue))
+        }
+      />
+      {showClipInsetSides && (
+        <div className="grid grid-cols-4 gap-2">
+          <MetricField
+            label="T"
+            value={formatPxMetricValue(clipInsetSides.top)}
+            disabled={disabled}
+            onCommit={(next) => commitClipInsetSide("top", next)}
+          />
+          <MetricField
+            label="R"
+            value={formatPxMetricValue(clipInsetSides.right)}
+            disabled={disabled}
+            onCommit={(next) => commitClipInsetSide("right", next)}
+          />
+          <MetricField
+            label="B"
+            value={formatPxMetricValue(clipInsetSides.bottom)}
+            disabled={disabled}
+            onCommit={(next) => commitClipInsetSide("bottom", next)}
+          />
+          <MetricField
+            label="L"
+            value={formatPxMetricValue(clipInsetSides.left)}
+            disabled={disabled}
+            onCommit={(next) => commitClipInsetSide("left", next)}
+          />
+        </div>
+      )}
+    </>
+  );
+}

packages/studio/src/components/editor/propertyPanelFlatPrimitives.test.tsx

@@ -89,8 +89,8 @@ describe("FlatSegmentedRow", () => {
       <FlatSegmentedRow
         label="Align"
         options={[
-          { key: "left", node: "L", active: false },
-          { key: "right", node: "R", active: true },
+          { key: "left", node: "L", label: "left", active: false },
+          { key: "right", node: "R", label: "right", active: true },
         ]}
         onChange={onChange}
       />,
@@ -105,6 +105,25 @@ describe("FlatSegmentedRow", () => {
     expect(onChange).toHaveBeenCalledWith("left");
     act(() => root.unmount());
   });
+
+  it("gives each option an accessible name and pressed state — glyphs alone (e.g. two 'A' buttons) aren't a valid accessible name", () => {
+    const { host, root } = renderInto(
+      <FlatSegmentedRow
+        label="Case · Style"
+        options={[
+          { key: "normal", node: "A", label: "upright", active: true },
+          { key: "italic", node: "A", label: "italic", active: false },
+        ]}
+        onChange={vi.fn()}
+      />,
+    );
+    const options = host.querySelectorAll<HTMLButtonElement>('[data-flat-segment="true"]');
+    expect(options[0]?.getAttribute("aria-label")).toBe("upright");
+    expect(options[0]?.getAttribute("aria-pressed")).toBe("true");
+    expect(options[1]?.getAttribute("aria-label")).toBe("italic");
+    expect(options[1]?.getAttribute("aria-pressed")).toBe("false");
+    act(() => root.unmount());
+  });
 });
 
 describe("FlatGroupHeader", () => {
@@ -554,6 +573,130 @@ describe("FlatSlider — Grade extensions", () => {
     act(() => root.unmount());
   });
 
+  it("disables the reset button when the slider itself is disabled", () => {
+    const onReset = vi.fn();
+    const { host, root } = renderInto(
+      <FlatSlider
+        label="Exposure"
+        value={20}
+        min={0}
+        max={100}
+        tier="explicitCustom"
+        displayValue="20"
+        disabled
+        onReset={onReset}
+        onCommit={vi.fn()}
+      />,
+    );
+    const resetButton = host.querySelector<HTMLButtonElement>('[data-flat-slider-reset="true"]');
+    expect(resetButton?.disabled).toBe(true);
+    act(() => resetButton?.dispatchEvent(new MouseEvent("click", { bubbles: true })));
+    expect(onReset).not.toHaveBeenCalled();
+    act(() => root.unmount());
+  });
+
+  it("a trailing throttled commit uses the current render's onCommit, not the one captured when it was scheduled", () => {
+    vi.useFakeTimers();
+    const onCommitA = vi.fn();
+    const { host, root } = renderInto(
+      <FlatSlider
+        label="Exposure"
+        value={0}
+        min={-100}
+        max={100}
+        tier="explicitCustom"
+        displayValue="0"
+        onCommit={onCommitA}
+      />,
+    );
+    const track = host.querySelector<HTMLElement>('[data-flat-slider-track="true"]');
+    if (!track) throw new Error("expected a track element");
+    Object.defineProperty(track, "getBoundingClientRect", {
+      value: () => ({ left: 0, width: 200, top: 0, height: 20, right: 200, bottom: 20 }),
+    });
+    act(() => {
+      // Leading-edge commit fires synchronously with onCommitA (clientX 150
+      // on a -100..100 track maps to 50, distinct from the initial value 0).
+      track.dispatchEvent(
+        new PointerEvent("pointerdown", { bubbles: true, clientX: 150, pointerId: 1 }),
+      );
+    });
+    expect(onCommitA).toHaveBeenCalledTimes(1);
+    act(() => {
+      // Within the 40ms throttle window — queues a trailing commit (to 80,
+      // distinct from the just-committed 50) instead of firing immediately.
+      track.dispatchEvent(
+        new PointerEvent("pointermove", { bubbles: true, clientX: 180, pointerId: 1 }),
+      );
+    });
+    expect(onCommitA).toHaveBeenCalledTimes(1);
+    // Simulate the real-world race: something else causes this slider to
+    // re-render with a NEW onCommit closure before the queued timer fires
+    // (e.g. Grade's per-detail onCommit spreads the render-time whole
+    // grading object, so a different control committing in between produces
+    // a fresh closure). The stale closure must not win.
+    const onCommitB = vi.fn();
+    act(() => {
+      root.render(
+        <FlatSlider
+          label="Exposure"
+          value={0}
+          min={-100}
+          max={100}
+          tier="explicitCustom"
+          displayValue="0"
+          onCommit={onCommitB}
+        />,
+      );
+    });
+    act(() => {
+      vi.advanceTimersByTime(45);
+    });
+    expect(onCommitB).toHaveBeenCalledTimes(1);
+    expect(onCommitB).toHaveBeenCalledWith(80);
+    expect(onCommitA).toHaveBeenCalledTimes(1);
+    act(() => root.unmount());
+    vi.useRealTimers();
+  });
+
+  it("flushes a still-queued trailing commit on unmount instead of dropping it", () => {
+    vi.useFakeTimers();
+    const onCommit = vi.fn();
+    const { host, root } = renderInto(
+      <FlatSlider
+        label="Opacity"
+        value={5}
+        min={0}
+        max={100}
+        tier="explicitCustom"
+        displayValue="5%"
+        onCommit={onCommit}
+      />,
+    );
+    const track = host.querySelector<HTMLElement>('[data-flat-slider-track="true"]');
+    if (!track) throw new Error("expected a track element");
+    Object.defineProperty(track, "getBoundingClientRect", {
+      value: () => ({ left: 0, width: 200, top: 0, height: 20, right: 200, bottom: 20 }),
+    });
+    act(() => {
+      track.dispatchEvent(
+        new PointerEvent("pointerdown", { bubbles: true, clientX: 20, pointerId: 1 }),
+      );
+    });
+    expect(onCommit).toHaveBeenCalledTimes(1);
+    act(() => {
+      // Queues a trailing commit that never gets to fire before unmount.
+      track.dispatchEvent(
+        new PointerEvent("pointermove", { bubbles: true, clientX: 160, pointerId: 1 }),
+      );
+    });
+    expect(onCommit).toHaveBeenCalledTimes(1);
+    act(() => root.unmount());
+    expect(onCommit).toHaveBeenCalledTimes(2);
+    expect(onCommit).toHaveBeenNthCalledWith(2, 80);
+    vi.useRealTimers();
+  });
+
   it("supports keyboard operation: focusable, arrow keys step, Home/End clamp to range", () => {
     const onCommit = vi.fn();
     const { host, root } = renderInto(
@@ -728,6 +871,31 @@ describe("FlatSelectRow — label/value options", () => {
     expect(options).toEqual(["normal", "multiply", "screen"]);
     act(() => root.unmount());
   });
+
+  it("preserves a valid authored value outside the preset list instead of misrepresenting it as the first option", () => {
+    const onChange = vi.fn();
+    const { host, root } = renderInto(
+      <FlatSelectRow
+        label="Blend"
+        value="difference"
+        options={["normal", "multiply", "screen", "overlay"]}
+        tier="explicitCustom"
+        onChange={onChange}
+      />,
+    );
+    const select = host.querySelector<HTMLSelectElement>("select");
+    // A native <select> whose `value` matches no <option> falls back to
+    // selectedIndex 0 — silently showing "normal" as selected even though
+    // the real persisted value is "difference". The row must add an option
+    // for the current value so it's genuinely representable.
+    expect(select?.value).toBe("difference");
+    const options = Array.from(host.querySelectorAll("option")).map((o) => o.textContent);
+    expect(options).toContain("difference");
+    // And reselecting the (still-present) first preset must be an explicit
+    // user choice, not something that already happened silently.
+    expect(onChange).not.toHaveBeenCalled();
+    act(() => root.unmount());
+  });
 });
 
 describe("FlatToggle", () => {

packages/studio/src/components/editor/propertyPanelFlatPrimitives.tsx

@@ -87,6 +87,10 @@ export function FlatRow({
 export interface FlatSegmentOption {
   key: string;
   node: ReactNode;
+  /** Accessible name — the glyph alone (e.g. two indistinguishable "A"
+   *  buttons for upright vs. italic) isn't a valid accessible name on its
+   *  own. */
+  label: string;
   active: boolean;
 }
 
@@ -114,6 +118,8 @@ export function FlatSegmentedRow({
             <button
               type="button"
               data-flat-segment="true"
+              aria-label={option.label}
+              aria-pressed={option.active}
               disabled={disabled}
               onClick={() => onChange(option.key)}
               className={`px-1.5 py-1 text-[11px] transition-colors disabled:cursor-not-allowed ${
@@ -286,6 +292,14 @@ export function FlatSlider({
   // prop, so the release flush must dedupe against what we just sent, not
   // against the stale prop, or the same value commits twice.
   const lastCommittedRef = useRef(value);
+  // Always the current render's onCommit — read inside the throttle timer
+  // instead of closing over the callback at schedule time. A caller whose
+  // onCommit spreads other current state (e.g. Grade's "...grading, details:
+  // {...}") would otherwise let a queued trailing commit fire ~40ms later
+  // with a stale snapshot and silently revert whatever the user changed on a
+  // different control in between.
+  const onCommitRef = useRef(onCommit);
+  onCommitRef.current = onCommit;
 
   useEffect(() => {
     if (draggingRef.current) return;
@@ -294,7 +308,14 @@ export function FlatSlider({
   }, [value]);
   useEffect(
     () => () => {
-      if (commitTimerRef.current) clearTimeout(commitTimerRef.current);
+      if (commitTimerRef.current) {
+        clearTimeout(commitTimerRef.current);
+        // Flush rather than drop a still-queued edit — this only fires if the
+        // component unmounts mid-drag (e.g. selection changes away), and
+        // silently discarding the user's last dragged position would look
+        // like data loss.
+        if (pendingRef.current !== null) onCommitRef.current(pendingRef.current);
+      }
     },
     [],
   );
@@ -316,7 +337,7 @@ export function FlatSlider({
     lastCommitAtRef.current = Date.now();
     if (nextDraft !== lastCommittedRef.current) {
       lastCommittedRef.current = nextDraft;
-      onCommit(nextDraft);
+      onCommitRef.current(nextDraft);
     }
   };
   const scheduleCommit = (nextDraft: number) => {
@@ -346,6 +367,7 @@ export function FlatSlider({
         aria-valuemax={max}
         aria-disabled={disabled}
         tabIndex={disabled ? -1 : 0}
+        style={{ touchAction: "none" }}
         className={`relative h-5 flex-1 ${disabled ? "cursor-not-allowed" : "cursor-pointer"}`}
         onPointerDown={(e) => {
           if (disabled) return;
@@ -429,8 +451,9 @@ export function FlatSlider({
               type="button"
               data-flat-slider-reset="true"
               title="Remove — fall back to default"
+              disabled={disabled}
               onClick={onReset}
-              className="text-panel-text-3 hover:text-panel-text-1"
+              className="text-panel-text-3 hover:text-panel-text-1 disabled:cursor-not-allowed disabled:opacity-40"
             >
               <RotateCcw size={11} />
             </button>
@@ -465,6 +488,17 @@ export function FlatSelectRow({
   const normalizedOptions = options.map((option) =>
     typeof option === "string" ? { value: option, label: option } : option,
   );
+  // A valid authored value outside the preset list (e.g. a `mix-blend-mode`
+  // or `object-position` this row doesn't offer as a preset) must not be
+  // silently misrepresented as the first option — the native <select> falls
+  // back to selectedIndex 0 when `value` matches no <option>, and reselecting
+  // that visible-but-wrong preset overwrites the real persisted value. Prepend
+  // the current value so it's always representable, matching legacy
+  // `SelectField`'s same guard.
+  const renderedOptions =
+    value && !normalizedOptions.some((option) => option.value === value)
+      ? [{ value, label: value }, ...normalizedOptions]
+      : normalizedOptions;
   return (
     <div className="group flex min-h-[30px] items-center justify-between">
       <span className={`text-[11px] ${VALUE_TIER_LABEL_CLASS[tier]}`}>{label}</span>
@@ -476,7 +510,7 @@ export function FlatSelectRow({
             onChange={(e) => onChange(e.target.value)}
             className={`appearance-none bg-transparent text-right font-mono text-[11px] outline-none disabled:cursor-not-allowed ${VALUE_TIER_VALUE_CLASS[tier]}`}
           >
-            {normalizedOptions.map((option) => (
+            {renderedOptions.map((option) => (
               <option key={option.value} value={option.value}>
                 {option.label}
               </option>

packages/studio/src/components/editor/propertyPanelFlatStyleSections.tsx

@@ -11,24 +11,19 @@ import {
 import {
   buildBoxShadowPresetValue,
   buildClipPathValue,
-  buildInsetClipPathSides,
-  buildInsetClipPathValue,
   buildStrokeStyleUpdates,
   buildStrokeWidthStyleUpdates,
   extractBackgroundImageUrl,
   formatNumericValue,
   formatPxMetricValue,
-  getClipPathInsetPx,
   getCssFilterFunctionPx,
   inferBoxShadowPreset,
   inferClipPathPreset,
   normalizePanelPxValue,
-  parseInsetClipPathSides,
   parseNumericValue,
   parsePxMetricValue,
   setCssFilterFunctionPx,
   type BoxShadowPreset,
-  type ClipPathInsetSides,
 } from "./propertyPanelHelpers";
 import {
   FlatRow,
@@ -36,7 +31,7 @@ import {
   FlatSelectRow,
   FlatSlider,
 } from "./propertyPanelFlatPrimitives";
-import { MetricField } from "./propertyPanelPrimitives";
+import { FlatMaskInsetRows } from "./propertyPanelFlatMaskInsetRows";
 import { resolveValueTier } from "./propertyPanelValueTier";
 import { ColorField } from "./propertyPanelColor";
 import { GradientField, ImageFillField } from "./propertyPanelFill";
@@ -96,9 +91,14 @@ function FlatFillFields({
       <FlatSegmentedRow
         label="Fill"
         options={[
-          { key: "Solid", node: "Solid", active: preferredFillMode === "Solid" },
-          { key: "Gradient", node: "Gradient", active: preferredFillMode === "Gradient" },
-          { key: "Image", node: "Image", active: preferredFillMode === "Image" },
+          { key: "Solid", node: "Solid", label: "Solid", active: preferredFillMode === "Solid" },
+          {
+            key: "Gradient",
+            node: "Gradient",
+            label: "Gradient",
+            active: preferredFillMode === "Gradient",
+          },
+          { key: "Image", node: "Image", label: "Image", active: preferredFillMode === "Image" },
         ]}
         disabled={styleEditingDisabled}
         onChange={handleFillModeChange}
@@ -435,90 +435,6 @@ function FlatOverflowMaskRows({
   );
 }
 
-// Flat Mask inset — uniform slider + per-side fields.
-function FlatMaskInsetRows({
-  clipPathValue,
-  radiusValue,
-  disabled,
-  onSetStyle,
-}: {
-  clipPathValue: string;
-  radiusValue: number;
-  disabled: boolean;
-  onSetStyle: (prop: string, value: string) => void | Promise<void>;
-}) {
-  const clipPathPreset = inferClipPathPreset(clipPathValue);
-  const parsedClipInsets = parseInsetClipPathSides(clipPathValue);
-  const clipInsetValue = getClipPathInsetPx(clipPathValue);
-  const clipInsetSides = parsedClipInsets ?? {
-    top: clipInsetValue,
-    right: clipInsetValue,
-    bottom: clipInsetValue,
-    left: clipInsetValue,
-    radius: radiusValue,
-  };
-  const showClipInsetSides = clipPathPreset === "inset" || parsedClipInsets != null;
-
-  const commitClipInsetSide = (side: keyof ClipPathInsetSides, nextValue: string) => {
-    const next = parsePxMetricValue(nextValue);
-    if (next == null) return;
-    const sides: ClipPathInsetSides = {
-      top: clipInsetSides.top,
-      right: clipInsetSides.right,
-      bottom: clipInsetSides.bottom,
-      left: clipInsetSides.left,
-    };
-    sides[side] = next;
-    void onSetStyle("clip-path", buildInsetClipPathSides(sides, clipInsetSides.radius));
-  };
-
-  return (
-    <>
-      <FlatSlider
-        label="Mask inset"
-        value={clipInsetValue}
-        min={0}
-        max={Math.max(120, Math.ceil(clipInsetValue))}
-        step={1}
-        tier={clipInsetValue > 0 ? "explicitCustom" : "default"}
-        displayValue={`${formatNumericValue(clipInsetValue)}px`}
-        disabled={disabled}
-        onCommit={(next) =>
-          void onSetStyle("clip-path", buildInsetClipPathValue(next, radiusValue))
-        }
-      />
-      {showClipInsetSides && (
-        <div className="grid grid-cols-4 gap-2">
-          <MetricField
-            label="T"
-            value={formatPxMetricValue(clipInsetSides.top)}
-            disabled={disabled}
-            onCommit={(next) => commitClipInsetSide("top", next)}
-          />
-          <MetricField
-            label="R"
-            value={formatPxMetricValue(clipInsetSides.right)}
-            disabled={disabled}
-            onCommit={(next) => commitClipInsetSide("right", next)}
-          />
-          <MetricField
-            label="B"
-            value={formatPxMetricValue(clipInsetSides.bottom)}
-            disabled={disabled}
-            onCommit={(next) => commitClipInsetSide("bottom", next)}
-          />
-          <MetricField
-            label="L"
-            value={formatPxMetricValue(clipInsetSides.left)}
-            disabled={disabled}
-            onCommit={(next) => commitClipInsetSide("left", next)}
-          />
-        </div>
-      )}
-    </>
-  );
-}
-
 /* ------------------------------------------------------------------ */
 /*  Flat Opacity slider                                                */
 /* ------------------------------------------------------------------ */

packages/studio/src/components/editor/propertyPanelFlatTextSection.test.tsx

@@ -210,7 +210,7 @@ describe("FlatTextFieldEditor controls", () => {
     act(() => root.unmount());
   });
 
-  it("lights up 'right' for text-align: end and commits the concrete 'right' value on click", () => {
+  it("lights up 'right' for text-align: end but re-clicking it is a no-op — preserves the logical value", () => {
     const onSetTextFieldStyle = vi.fn();
     const { host, root } = renderInto(
       <FlatTextSection
@@ -227,8 +227,32 @@ describe("FlatTextFieldEditor controls", () => {
     const rightButton = alignButtons.find((button) => button.textContent === "R");
     expect(rightButton).not.toBeUndefined();
     expect(rightButton?.className).toContain("border-panel-accent");
+    // Clicking the option that's already visually active for "end" must NOT
+    // rewrite it to the physical "right" — that would destroy the logical
+    // semantics and break RTL content, where "end" and "right" differ.
     act(() => rightButton?.dispatchEvent(new MouseEvent("click", { bubbles: true })));
-    expect(onSetTextFieldStyle).toHaveBeenCalledWith("a", "text-align", "right");
+    expect(onSetTextFieldStyle).not.toHaveBeenCalled();
+    act(() => root.unmount());
+  });
+
+  it("commits a genuine align change away from a logical value", () => {
+    const onSetTextFieldStyle = vi.fn();
+    const { host, root } = renderInto(
+      <FlatTextSection
+        element={makeSingleFieldElement({ computedStyles: { "text-align": "end" } })}
+        styles={{}}
+        fontAssets={[]}
+        onSetText={vi.fn()}
+        onSetTextFieldStyle={onSetTextFieldStyle}
+        onAddTextField={vi.fn()}
+        onRemoveTextField={vi.fn()}
+      />,
+    );
+    const alignButtons = segmentedRowButtons(host, "Align");
+    const centerButton = alignButtons.find((button) => button.textContent === "C");
+    expect(centerButton).not.toBeUndefined();
+    act(() => centerButton?.dispatchEvent(new MouseEvent("click", { bubbles: true })));
+    expect(onSetTextFieldStyle).toHaveBeenCalledWith("a", "text-align", "center");
     act(() => root.unmount());
   });
 

packages/studio/src/components/editor/propertyPanelFlatTextSection.tsx

@@ -33,10 +33,10 @@ const ALIGN_OPTIONS = [
 ];
 
 const CASE_OPTIONS = [
-  { key: "none", node: "–" },
-  { key: "uppercase", node: "AG" },
-  { key: "lowercase", node: "ag" },
-  { key: "capitalize", node: "Ag" },
+  { key: "none", label: "none", node: "–" },
+  { key: "uppercase", label: "uppercase", node: "AG" },
+  { key: "lowercase", label: "lowercase", node: "ag" },
+  { key: "capitalize", label: "capitalize", node: "Ag" },
 ];
 
 function FlatTextFieldEditor({
@@ -167,12 +167,23 @@ function FlatTextFieldEditor({
         options={ALIGN_OPTIONS.map((option) => ({
           key: option.key,
           node: option.node,
+          label: option.label,
           active:
             align === option.key ||
             (option.key === "left" && align === "start") ||
             (option.key === "right" && align === "end"),
         }))}
-        onChange={(next) => onSetTextFieldStyle(field.key, "text-align", next)}
+        onChange={(next) => {
+          // Re-clicking the option that's already visually active for a
+          // logical value (authored "start"/"end") must not rewrite it to
+          // the physical "left"/"right" — that destroys the logical
+          // semantics and is wrong for RTL content. Only write when the
+          // user actually picked a different alignment.
+          if ((next === "left" && align === "start") || (next === "right" && align === "end")) {
+            return;
+          }
+          onSetTextFieldStyle(field.key, "text-align", next);
+        }}
       />
       <FlatSegmentedRow
         label="Case · Style"
@@ -180,10 +191,11 @@ function FlatTextFieldEditor({
           ...CASE_OPTIONS.map((option) => ({
             key: option.key,
             node: option.node,
+            label: option.label,
             active: textTransform === option.key,
           })),
-          { key: "normal", node: "A", active: fontStyle === "normal" },
-          { key: "italic", node: "A", active: fontStyle === "italic" },
+          { key: "normal", node: "A", label: "upright", active: fontStyle === "normal" },
+          { key: "italic", node: "A", label: "italic", active: fontStyle === "italic" },
         ]}
         spacerAfterIndex={2}
         onChange={(next) => {

packages/studio/src/components/editor/useColorGradingController.test.ts

@@ -53,35 +53,48 @@ function makeElement(overrides: Partial<DomEditSelection> = {}): DomEditSelectio
 function HookHost({
   onState,
   onSetAttributeLive,
+  element,
 }: {
   onState: (state: ReturnType<typeof useColorGradingController>) => void;
   onSetAttributeLive: (attr: string, value: string | null) => void;
+  element: DomEditSelection;
 }) {
   const state = useColorGradingController({
     projectId: "proj",
-    element: makeElement(),
+    element,
     onSetAttributeLive,
   });
   onState(state);
   return null;
 }
 
-function renderHook(onSetAttributeLive: (attr: string, value: string | null) => void) {
+function renderHook(
+  onSetAttributeLive: (attr: string, value: string | null) => void,
+  initialElement: DomEditSelection = makeElement(),
+) {
   const host = document.createElement("div");
   document.body.append(host);
   const root = createRoot(host);
   let latest: ReturnType<typeof useColorGradingController> | undefined;
-  act(() => {
-    root.render(
-      React.createElement(HookHost, {
-        onState: (s: ReturnType<typeof useColorGradingController>) => (latest = s),
-        onSetAttributeLive,
-      }),
-    );
-  });
+  const renderWith = (element: DomEditSelection) => {
+    act(() => {
+      root.render(
+        React.createElement(HookHost, {
+          onState: (s: ReturnType<typeof useColorGradingController>) => (latest = s),
+          onSetAttributeLive,
+          element,
+        }),
+      );
+    });
+  };
+  renderWith(initialElement);
   return {
     root,
-    get state() {
+    rerenderWithElement: renderWith,
+    // A method, not a getter — `const { state } = renderHook(...)` would
+    // destructure a getter into a one-time snapshot, silently going stale
+    // after the first state change. Call `.getState()` fresh every time.
+    getState(): ReturnType<typeof useColorGradingController> {
       if (!latest) throw new Error("hook did not render");
       return latest;
     },
@@ -90,19 +103,20 @@ function renderHook(onSetAttributeLive: (attr: string, value: string | null) =>
 
 describe("useColorGradingController", () => {
   it("starts with the neutral (inactive) grading and idle compare state", () => {
-    const { root, state } = renderHook(vi.fn());
-    expect(state.grading.preset).toBe("neutral");
-    expect(state.compareEnabled).toBe(false);
+    const { root, getState } = renderHook(vi.fn());
+    expect(getState().grading.preset).toBe("neutral");
+    expect(getState().compareEnabled).toBe(false);
     act(() => root.unmount());
   });
 
   it("commitColorGrading updates grading state synchronously and schedules a debounced persist", async () => {
     vi.useFakeTimers();
     const onSetAttributeLive = vi.fn();
-    const { root, state } = renderHook(onSetAttributeLive);
+    const { root, getState } = renderHook(onSetAttributeLive);
     act(() => {
-      state.commitColorGrading(freshPopGrading());
+      getState().commitColorGrading(freshPopGrading());
     });
+    expect(getState().grading.preset).toBe("fresh-pop");
     expect(onSetAttributeLive).not.toHaveBeenCalled();
     act(() => {
       vi.advanceTimersByTime(400);
@@ -116,14 +130,95 @@ describe("useColorGradingController", () => {
   });
 
   it("resetGrading returns to the neutral preset", () => {
-    const { root, state } = renderHook(vi.fn());
+    const { root, getState } = renderHook(vi.fn());
     act(() => {
-      state.commitColorGrading(freshPopGrading());
+      getState().commitColorGrading(freshPopGrading());
     });
     act(() => {
-      state.resetGrading();
+      getState().resetGrading();
     });
-    expect(state.grading.preset).toBe("neutral");
+    expect(getState().grading.preset).toBe("neutral");
     act(() => root.unmount());
   });
+
+  it("resets grading/compare state when selection changes to a different element", () => {
+    const { root, getState, rerenderWithElement } = renderHook(
+      vi.fn(),
+      makeElement({ id: "s1-bg" }),
+    );
+    act(() => {
+      getState().commitColorGrading(freshPopGrading());
+    });
+    expect(getState().grading.preset).toBe("fresh-pop");
+    // A different element, with no persisted grading of its own — without a
+    // reset, this hook (unlike the legacy component it was extracted from,
+    // which remounts via a `key={selectionIdentityKey}`) would keep showing
+    // the previous element's grading.
+    rerenderWithElement(makeElement({ id: "s2-bg" }));
+    expect(getState().grading.preset).toBe("neutral");
+    act(() => root.unmount());
+  });
+
+  it("cancels a pending persist scheduled for the previous element when selection changes before it flushes", () => {
+    vi.useFakeTimers();
+    const onSetAttributeLive = vi.fn();
+    const { root, getState, rerenderWithElement } = renderHook(
+      onSetAttributeLive,
+      makeElement({ id: "s1-bg" }),
+    );
+    act(() => {
+      getState().commitColorGrading(freshPopGrading());
+    });
+    // Switch selection before the 350ms debounce flushes — the queued write
+    // targeted the OLD element and must not land on whatever is selected now.
+    act(() => {
+      vi.advanceTimersByTime(200);
+    });
+    rerenderWithElement(makeElement({ id: "s2-bg" }));
+    act(() => {
+      vi.advanceTimersByTime(400);
+    });
+    expect(onSetAttributeLive).not.toHaveBeenCalled();
+    act(() => root.unmount());
+    vi.useRealTimers();
+  });
+
+  it("does not permanently cache a non-OK media/metadata response — the next mount retries", async () => {
+    const videoWithSrc = () => {
+      const el = document.createElement("video");
+      el.setAttribute("src", "clip.mp4");
+      return el;
+    };
+    const fetchMock = vi
+      .fn()
+      .mockResolvedValueOnce({ ok: false } as Response)
+      .mockResolvedValueOnce({
+        ok: true,
+        json: () =>
+          Promise.resolve({ metadata: { kind: "video", color: { dynamicRange: "hdr" } } }),
+      } as unknown as Response);
+    vi.stubGlobal("fetch", fetchMock);
+
+    const first = renderHook(vi.fn(), makeElement({ id: "retry-asset", element: videoWithSrc() }));
+    await act(async () => {
+      await Promise.resolve();
+    });
+    expect(first.getState().mediaMetadata).toBeNull();
+    act(() => first.root.unmount());
+
+    // A second, independent mount for the SAME asset path — if the failed
+    // response had been cached, this would never re-fetch and mediaMetadata
+    // would stay null forever.
+    const second = renderHook(
+      vi.fn(),
+      makeElement({ id: "retry-asset-2", element: videoWithSrc() }),
+    );
+    await act(async () => {
+      await Promise.resolve();
+    });
+    expect(fetchMock).toHaveBeenCalledTimes(2);
+    expect(second.getState().mediaMetadata?.color.dynamicRange).toBe("hdr");
+    act(() => second.root.unmount());
+    vi.unstubAllGlobals();
+  });
 });

packages/studio/src/components/editor/useColorGradingController.ts

@@ -12,7 +12,7 @@ import {
   trackStudioPendingEdit,
 } from "../../utils/studioPendingEdits";
 import type { DomEditSelection } from "./domEditing";
-import { stripQueryAndHash } from "./propertyPanelHelpers";
+import { selectionIdentityKey, stripQueryAndHash } from "./propertyPanelHelpers";
 import {
   acceptStudioRuntimeMessage,
   postRuntimeControlMessage,
@@ -196,6 +196,38 @@ export function useColorGradingController({
   onSetAttributeLiveRef.current = onSetAttributeLive;
   latestGradingRef.current = grading;
   compareEnabledRef.current = compareEnabled;
+
+  // Reset all per-element state when the selection changes to a different
+  // element — unlike the legacy ColorGradingSection (remounted via a
+  // `key={selectionIdentityKey(element)}` from its parent), this hook is
+  // called unconditionally on every render, so nothing naturally remounts it.
+  // Without this, switching selection reuses the previous element's grading/
+  // compare/mediaMetadata state and can commit stale pending work onto the
+  // new target. Adjusting state during render (comparing against a ref) is
+  // React's documented pattern for this — it resolves in the same render
+  // pass instead of flashing the stale state for one frame via useEffect.
+  const identityKey = selectionIdentityKey(element);
+  const identityKeyRef = useRef(identityKey);
+  if (identityKeyRef.current !== identityKey) {
+    identityKeyRef.current = identityKey;
+    if (persistTimerRef.current) {
+      clearTimeout(persistTimerRef.current);
+      persistTimerRef.current = null;
+    }
+    pendingPersistValueRef.current = undefined;
+    for (const timer of statusTimersRef.current) clearTimeout(timer);
+    statusTimersRef.current = [];
+    const freshGrading = readColorGradingFromElement(element);
+    latestGradingRef.current = freshGrading;
+    setGrading(freshGrading);
+    setCompareEnabled(false);
+    compareEnabledRef.current = false;
+    setApplyScope("source-file");
+    setApplyBusy(false);
+    setRuntimeStatus({ state: "pending", message: "Waiting for runtime" });
+    setMediaMetadata(null);
+  }
+
   const target = useMemo(
     (): HfColorGradingTarget => ({
       id: element.id ?? null,
@@ -225,18 +257,29 @@ export function useColorGradingController({
       )}`,
       { signal: controller.signal },
     )
-      .then((response) => (response.ok ? response.json() : null))
-      .then((data: MediaMetadataResponse | null) => {
+      .then(async (response) => {
+        if (!response.ok) return { ok: false as const };
+        const data: MediaMetadataResponse | null = await response.json();
+        return { ok: true as const, metadata: data?.metadata ?? null };
+      })
+      .then((result) => {
         if (controller.signal.aborted) return;
-        const metadata = data?.metadata ?? null;
-        MEDIA_METADATA_CACHE.set(cacheKey, metadata);
-        setMediaMetadata(metadata);
+        // Only cache a definitive answer from a successful response — a non-OK
+        // status is a transient/server failure, not a stable "no metadata"
+        // result, and caching it would suppress the HDR banner for this asset
+        // for the page's whole lifetime. Leave the key absent so the next
+        // selection retries.
+        if (!result.ok) {
+          setMediaMetadata(null);
+          return;
+        }
+        MEDIA_METADATA_CACHE.set(cacheKey, result.metadata);
+        setMediaMetadata(result.metadata);
       })
       .catch(() => {
-        // Don't cache a transient fetch failure — a cached null would suppress
-        // the HDR banner for this asset for the page's whole lifetime. Leave the
-        // key absent so the next selection retries. (A successful response with
-        // no metadata still caches null above, which IS a stable answer.)
+        // Same reasoning as the non-OK branch above: don't cache a network-
+        // level fetch failure either.
+        if (!controller.signal.aborted) setMediaMetadata(null);
       });
     return () => controller.abort();
   }, [projectId, selectedAssetPath]);