diff --git a/TESTING.md b/TESTING.md
index 312671e3..4e37aba5 100644
--- a/TESTING.md
+++ b/TESTING.md
@@ -5705,6 +5705,23 @@ npm run --prefix tools/vendor test:workflows -- workspace-system-backups.spec.mj
   --project chromium --project touch --project firefox --project webkit
 ```
 
+## Sticky chrome (#531)
+
+Beyond the concept, from the maintainer's test of #528; the concept is unchanged. `workspace-sticky-chrome.spec.mjs` holds these.
+
+- **D186:** the selection bars (Images `#bulkbar`, Library `#library-bulkbar`; there are no others) are sticky: under the
+  top bar at the top of the page, and at the top of the window once that non-sticky top bar has scrolled away (one rule
+  in workspace.css). While the bar's flow place is above the window, its appearing, resizing or leaving does not move the cards
+  (`keepingPlace`). Focused card controls and the Images panel keep clear of it (`--selection-bar-block`). At 700px and below
+  the bar is one row that scrolls sideways. After a bulk action finishes the page scrolls to the top and refreshes the
+  list; Set category, Delete… and Return to library clear the selection as before, while tagging and collections keep
+  it (D85, D138). Export metadata changes nothing, so it stays put. Single-image actions from the inspector and viewer stay put.
+- **D187:** Back to top: one shell chip past 200px of scroll, above the toast's spot; it rises only for a toast taller than two lines. It never animates, because the
+  pages' height corrections would cancel a smooth scroll, and focus moves to `#workspace-main`. D42's band grows to 140px.
+- **D188:** the Needs review panel is sticky like the Images panel, with its own scroll on a window under 720px tall, and static at 700px and below.
+- **D189:** where a panel is one column (static): Info brings the panel into view. On
+  Images the panel follows the whole list, past infinite scroll, so loading waits for the reader's next move (wheel, touch or key) rather than pushing the panel away.
+
 ## Workspace data fields for the concept pages (#249)
 
 These fields are additive. The legacy `/prompt_manager/images/output` listing (no
diff --git a/tests/browser/images-concept.spec.mjs b/tests/browser/images-concept.spec.mjs
index 8851c1f1..55866eab 100644
--- a/tests/browser/images-concept.spec.mjs
+++ b/tests/browser/images-concept.spec.mjs
@@ -474,7 +474,10 @@ for(const [width,height] of SIZES)for(const theme of THEMES)test(`images selecti
     expect.soft(actual.bulkbar.bar.items.map(item=>item.text),'production bar').toEqual(['1 selected','Add tags','Auto-tag selected',
         'Set category','Add to collection','Export metadata','Delete…','Clear']);
     expect.soft(compare(empty,emptyActual,manifest,['bulkbar','cards','panel']),'nothing checked').toEqual([]);
-    expect.soft(compare(oracle,actual,manifest,['bulkbar','cards','panel']),'one card checked').toEqual([]);
+    // D186: the panel's sticky offset clears the shown bar; at one column the bar is one sideways row (its items are checked above).
+    const stuckPanel={...oracle,panel:{...oracle.panel,...(width<=700?{top:actual.panel.top}:{}),box:{...oracle.panel.box,top:actual.panel.box.top}}};
+    expect(parseFloat(actual.panel.box.top)).toBeGreaterThanOrEqual(20);
+    expect.soft(compare(stuckPanel,actual,manifest,width<=700?['panel']:['bulkbar','cards','panel']),'one card checked').toEqual([]);
     // The bar comparison notices a change to the production bar.
     await mutate(page,{css:'.bulkbar { padding: 4px }'});
     expect(compare(oracle,await inventoryOf(page,'#workspace-main'),manifest,['bulkbar']).map(item=>item.path)).toContain('bulkbar.bar.paddingTop');
diff --git a/tests/browser/library-concept.spec.mjs b/tests/browser/library-concept.spec.mjs
index b6887c86..19536b7a 100644
--- a/tests/browser/library-concept.spec.mjs
+++ b/tests/browser/library-concept.spec.mjs
@@ -374,7 +374,9 @@ for(const [width,height] of SIZES)for(const theme of THEMES)test(`the Library se
     await captureCanonicalState(page,testInfo,`production-library-selection-${width}-${theme}`);
     await testInfo.attach('library-selection',{body:JSON.stringify({reference,actual},null,2),contentType:'application/json'});
     expect(reference.bar.buttons.map(button=>button.text),'the concept bar has every Library action').toEqual(['Add tags','Set category','Clear']);
-    expect(actual).toEqual(reference);
+    // D186: at one column the bar is one row that scrolls sideways, with the same buttons.
+    const mapped=width<=700?{...reference,bar:{...reference.bar,flexWrap:'nowrap',buttons:reference.bar.buttons.map((button,index)=>({...button,left:actual.bar.buttons[index].left,top:actual.bar.buttons[index].top}))}}:reference;
+    expect(actual).toEqual(mapped);
     // The comparison notices a moved checkbox (spec §7 mutation check).
     await mutate(page,{css:'.prompt-card .image-overlays { inset: 20px 9px auto }'});
     expect((await measureSelection(page,{card:CARDS,main:'#workspace-main'})).overlay.top).not.toBe(reference.overlay.top);
diff --git a/tests/browser/tagging-canonical-comparison.mjs b/tests/browser/tagging-canonical-comparison.mjs
index a959bc2f..ef112625 100644
--- a/tests/browser/tagging-canonical-comparison.mjs
+++ b/tests/browser/tagging-canonical-comparison.mjs
@@ -231,6 +231,9 @@ export function mapConceptReview(reference,actual) {
     const actualActions=findNode(actual.main,'div.dialog-actions');
     let cardIndex=0;
     let main={...reference.main,id:actual.main.id};
+    // D188: the Resolve panel is sticky.
+    const actualPanel=findNode(actual.main,'div.gallery-layout')?.children[1];
+    if(actualPanel)main=editNodes(main,'div.gallery-layout',layout=>({...layout,children:layout.children.map((child,index)=>index===1?{...child,position:actualPanel.position}:child)}));
     let noticeLoss=0;
     main=editNodes(main,'div.notice',notice=>{
         const chip=notice.children.find(child=>child.tag==='span.chip');
diff --git a/tests/browser/workspace-sticky-chrome.spec.mjs b/tests/browser/workspace-sticky-chrome.spec.mjs
new file mode 100644
index 00000000..2fb311d7
--- /dev/null
+++ b/tests/browser/workspace-sticky-chrome.spec.mjs
@@ -0,0 +1,321 @@
+// #531 (D186-D189): the selection bars stay in view, a Back to top chip follows the page, and the side panels stay with
+// you. Beyond the concept; the concept itself is unchanged.
+import { startCoverage, saveCoverage } from '../../tools/vendor/browser-coverage.mjs';
+import { test, expect } from './fixtures.mjs';
+
+const IMAGES = '/prompt_manager/workspace#/images';
+const LIBRARY = '/prompt_manager/workspace#/library';
+const REVIEW = '/prompt_manager/workspace#/review';
+const PHONE = { width: 390, height: 844 };
+const imageCards = page => page.locator('#image-grid article[data-image-key]');
+const promptCards = page => page.locator('article[data-prompt-id]');
+const imageBar = page => page.locator('#bulkbar > .bulkbar');
+const libraryBar = page => page.locator('#library-bulkbar > .bulkbar');
+const chip = page => page.getByRole('button', { name: 'Back to top', exact: true });
+const toast = page => page.locator('#workspace-toast');
+const reviewPanel = page => page.getByRole('region', { name: 'Resolve the association', exact: true });
+const reviewCards = page => page.locator('.review-queue article.media-card');
+
+const box = locator => locator.evaluate(node => {
+    const { top, bottom, left, right } = node.getBoundingClientRect();
+    return { top, bottom, left, right };
+});
+const overlaps = (a, b) => a.left < b.right && b.left < a.right && a.top < b.bottom && b.top < a.bottom;
+/** Scroll the window to `y` and wait for the frame that applied it. */
+async function scrollToY(page, y) {
+    await page.evaluate(target => new Promise(resolve => {
+        scrollTo({ top: target, behavior: 'instant' });
+        requestAnimationFrame(() => requestAnimationFrame(resolve));
+    }), y);
+}
+/** The first card wholly below `below` px, by its index in the list. */
+async function cardBelow(cards, below) {
+    const count = await cards.count();
+    for (let index = 0; index < count; index++) {
+        const card = cards.nth(index);
+        if ((await box(card)).top <= below) continue;
+        // By its key, not its position: the mounted window moves as the page does.
+        const key = await card.evaluate(node => ['imageKey', 'promptId', 'reviewId'].map(name => [name, node.dataset[name]]).find(([, value]) => value));
+        const attribute = key[0].replace(/[A-Z]/g, letter => `-${letter.toLowerCase()}`);
+        return cards.page().locator(`article[data-${attribute}=${JSON.stringify(key[1])}]`);
+    }
+    throw new Error(`no card below ${below}`);
+}
+async function openImages(page, request, extra = 100) {
+    await expect(await request.post('/__test__/reset', { data: { extra_images: extra } })).toBeOK();
+    await page.goto(IMAGES);
+    await expect(imageCards(page).first()).toBeVisible();
+}
+async function openLibrary(page, request, extra = 40) {
+    await expect(await request.post('/__test__/reset', { data: { native_library: true, extra_prompts: extra } })).toBeOK();
+    await page.goto(LIBRARY);
+    await expect(promptCards(page).first()).toBeVisible();
+}
+async function openReview(page, request, items = 30) {
+    await expect(await request.post('/__test__/review/reset', { data: { items } })).toBeOK();
+    await page.goto(REVIEW);
+    await expect(reviewPanel(page).getByRole('combobox', { name: 'Sampler context', exact: true })).toBeEnabled();
+}
+const inViewport = (rect, page) => rect.top >= 0 && rect.bottom <= page.viewportSize().height;
+
+test.beforeEach(async ({ page, browserName }) => { await startCoverage(page, browserName); });
+test.afterEach(async ({ page, browserName }, testInfo) => { await saveCoverage(page, browserName, testInfo); });
+
+for (const viewport of [null, PHONE]) {
+    const label = viewport ? ' at 390px' : '';
+    test(`Images: selecting far down keeps the bar in view and the card in place${label}`, async ({ page, request }) => {
+        if (viewport) await page.setViewportSize(viewport);
+        await openImages(page, request);
+        await scrollToY(page, 1500);
+        const card = await cardBelow(imageCards(page), 300);
+        const before = (await box(card)).top;
+        await card.locator('.image-overlays input[type="checkbox"]').check();
+        await expect(imageBar(page).locator('strong')).toHaveText('1 selected');
+        expect(inViewport(await box(imageBar(page)), page)).toBe(true);
+        expect(Math.abs((await box(card)).top - before)).toBeLessThanOrEqual(1);
+        // Keep scrolling and selecting: the bar stays; Clear returns the card to its place too.
+        await scrollToY(page, 1900);
+        expect(inViewport(await box(imageBar(page)), page)).toBe(true);
+        const later = await cardBelow(imageCards(page), 300);
+        await later.locator('.image-overlays input[type="checkbox"]').check();
+        await expect(imageBar(page).locator('strong')).toHaveText('2 selected');
+        const held = (await box(later)).top;
+        await imageBar(page).getByRole('button', { name: 'Clear', exact: true }).click();
+        await expect(imageBar(page)).toHaveCount(0);
+        expect(Math.abs((await box(later)).top - held)).toBeLessThanOrEqual(1);
+    });
+
+    test(`Library: selecting far down keeps the bar in view and the card in place${label}`, async ({ page, request }) => {
+        if (viewport) await page.setViewportSize(viewport);
+        await openLibrary(page, request);
+        await scrollToY(page, 2000);
+        await expect(promptCards(page).first()).toBeAttached();
+        const card = await cardBelow(promptCards(page), 250);
+        const before = (await box(card)).top;
+        await card.locator('.image-overlays input[type="checkbox"]').check();
+        await expect(libraryBar(page).locator('strong')).toHaveText('1 selected');
+        expect(inViewport(await box(libraryBar(page)), page)).toBe(true);
+        expect(Math.abs((await box(card)).top - before)).toBeLessThanOrEqual(1);
+        expect(await card.isVisible()).toBe(true);
+    });
+}
+
+test('the Images panel clears the stuck bar and a focused card is not left under it', async ({ page, request }) => {
+    await page.setViewportSize({ width: 1400, height: 900 });
+    await openImages(page, request);
+    await scrollToY(page, 1500);
+    await (await cardBelow(imageCards(page), 300)).locator('.image-overlays input[type="checkbox"]').check();
+    await expect(imageBar(page)).toBeVisible();
+    await expect.poll(async () => (await box(page.locator('#image-inspector'))).top).toBeGreaterThanOrEqual((await box(imageBar(page))).bottom);
+    expect(overlaps(await box(page.locator('#image-inspector')), await box(imageBar(page)))).toBe(false);
+    // A control scrolled to by focus lands below the bar; the bar's own controls do not move the page.
+    const y = await page.evaluate(() => scrollY);
+    await imageBar(page).getByRole('button', { name: 'Clear', exact: true }).focus();
+    expect(await page.evaluate(() => scrollY)).toBe(y);
+    const above = imageCards(page).first().locator('.image-overlays input[type="checkbox"]');
+    await above.focus();
+    expect((await box(above)).top).toBeGreaterThanOrEqual((await box(imageBar(page))).bottom);
+});
+
+test('Back to top shows off the top of a page, goes to the top and hands focus to the page', async ({ page, request }) => {
+    await openImages(page, request);
+    await expect(chip(page)).toBeHidden();
+    await scrollToY(page, 1500);
+    await expect(chip(page)).toBeVisible();
+    const loaded = await page.evaluate(() => document.querySelector('#result-count').textContent);
+    await chip(page).click();
+    await expect.poll(() => page.evaluate(() => scrollY)).toBe(0);
+    await expect(chip(page)).toBeHidden();
+    await expect(page.locator('#workspace-main')).toBeFocused();
+    expect(await page.evaluate(() => document.querySelector('#result-count').textContent)).toBe(loaded);
+    await expect(imageCards(page).first()).toBeInViewport();
+});
+
+test('Back to top on the virtualized Library lands on the first card and stays there', async ({ page, request }) => {
+    await openLibrary(page, request, 200);
+    // Past 120 loaded prompts the shelf mounts only a window of them (each pass reaches the next page's trigger).
+    await expect.poll(async () => {
+        await page.evaluate(() => scrollTo({ top: document.documentElement.scrollHeight, behavior: 'instant' }));
+        return page.locator('article[data-index="0"]').count();
+    }, { timeout: 30000 }).toBe(0);
+    await expect(chip(page)).toBeVisible();
+    await chip(page).click();
+    await expect.poll(() => page.evaluate(() => scrollY)).toBe(0);
+    await expect.poll(async () => Number(await promptCards(page).first().getAttribute('data-index'))).toBe(0);
+    await expect(promptCards(page).first()).toBeInViewport();
+    expect(await page.evaluate(() => new Promise(resolve => requestAnimationFrame(() => requestAnimationFrame(() => resolve(scrollY)))))).toBe(0);
+});
+
+test('Back to top jumps, under reduced motion and otherwise', async ({ page, request }) => {
+    await page.emulateMedia({ reducedMotion: 'reduce' });
+    await openImages(page, request, 20);
+    await scrollToY(page, 600);
+    await expect(chip(page)).toBeVisible();
+    const after = await chip(page).evaluate(node => { node.click(); return scrollY; });
+    expect(after).toBe(0);
+});
+
+for (const viewport of [{ width: 1280, height: 720 }, PHONE]) {
+    test(`Back to top moves clear of a toast and of the bar at ${viewport.width}px`, async ({ page, request }) => {
+        await page.setViewportSize(viewport);
+        await openImages(page, request);
+        await scrollToY(page, 1500);
+        await expect(chip(page)).toBeVisible();
+        await (await cardBelow(imageCards(page), 200)).locator('.image-overlays input[type="checkbox"]').check();
+        await expect(imageBar(page)).toBeVisible();
+        expect(overlaps(await box(chip(page)), await box(imageBar(page)))).toBe(false);
+        const alone = await box(chip(page));
+        await page.evaluate(() => {
+            document.getElementById('workspace-toast').textContent = 'A much longer message than most, one that keeps going, so that it wraps to more than two lines on the narrowest screen a phone will give this page to show it on, and then some more words again.';
+        });
+        await expect(toast(page)).not.toBeEmpty();
+        await expect.poll(async () => overlaps(await box(chip(page)), await box(toast(page)))).toBe(false);
+        expect((await box(chip(page))).bottom).toBeLessThanOrEqual((await box(toast(page))).top);
+        await expect(chip(page)).toBeInViewport();
+        await page.evaluate(() => { document.getElementById('workspace-toast').textContent = ''; });
+        await expect.poll(async () => Math.round((await box(chip(page))).bottom)).toBe(Math.round(alone.bottom));
+    });
+}
+
+test('a stuck bar at 390px is one row that keeps every action reachable', async ({ page, request }) => {
+    await page.setViewportSize(PHONE);
+    await openImages(page, request);
+    await scrollToY(page, 1500);
+    await (await cardBelow(imageCards(page), 200)).locator('.image-overlays input[type="checkbox"]').check();
+    await expect(imageBar(page)).toBeVisible();
+    expect((await box(imageBar(page))).bottom - (await box(imageBar(page))).top).toBeLessThan(80);
+    const clear = imageBar(page).getByRole('button', { name: 'Clear', exact: true });
+    await clear.scrollIntoViewIfNeeded();
+    await expect(clear).toBeInViewport();
+    await clear.click();
+    await expect(imageBar(page)).toHaveCount(0);
+});
+
+test('the Needs review panel stays with you, and its long content scrolls inside it', async ({ page, request }) => {
+    await page.setViewportSize({ width: 1400, height: 500 });
+    await openReview(page, request);
+    await scrollToY(page, 700);
+    await expect(reviewPanel(page)).toBeInViewport();
+    const rect = await box(reviewPanel(page));
+    expect(rect.top).toBeGreaterThanOrEqual(0);
+    expect(rect.bottom).toBeLessThanOrEqual(500);
+    const card = await cardBelow(reviewCards(page), 100);
+    await card.getByRole('button', { name: /^Inspect / }).click();
+    const name = await card.locator('.media-info').first().textContent();
+    expect(name).toBeTruthy();
+    await expect(reviewPanel(page)).toBeInViewport();
+    expect((await box(reviewPanel(page))).top).toBe(rect.top);
+});
+
+test('at 390px Info on a lower review card brings the panel into view', async ({ page, request }) => {
+    await page.setViewportSize(PHONE);
+    await openReview(page, request);
+    await expect(reviewPanel(page)).not.toBeInViewport();
+    const card = reviewCards(page).nth(3);
+    await card.scrollIntoViewIfNeeded();
+    await card.getByRole('button', { name: /^Inspect / }).click();
+    await expect(reviewPanel(page)).toBeInViewport();
+});
+
+// D189: at one column the Images panel follows the whole list: Info goes there, and a batch doesn't push it away.
+test('at 390px Info on an image brings its panel into view and loading waits for the next move', async ({ page, request }) => {
+    await page.setViewportSize(PHONE);
+    await openImages(page, request);
+    expect(await page.evaluate(() => scrollY)).toBe(0);
+    await expect(page.locator('#image-inspector')).not.toBeInViewport();
+    let reads = 0;
+    page.on('request', item => { if (new URL(item.url()).pathname.endsWith('/images/recent')) reads++; });
+    const card = imageCards(page).nth(3);
+    await card.scrollIntoViewIfNeeded();
+    await card.getByRole('button', { name: /^Inspect / }).click();
+    await expect(page.locator('#image-inspector')).toBeInViewport();
+    await expect(page.locator('#viewer-dialog')).toBeHidden();
+    const held = (await box(page.locator('#image-inspector'))).top;
+    await page.evaluate(() => new Promise(resolve => requestAnimationFrame(() => requestAnimationFrame(resolve))));
+    expect((await box(page.locator('#image-inspector'))).top).toBe(held);
+    expect(reads).toBe(0);
+    // The next move releases it: loading resumes.
+    const next = page.waitForRequest(item => new URL(item.url()).pathname.includes('/images'));
+    await page.mouse.wheel(0, 40);
+    await next;
+});
+
+// Review's review-state load more is a button, so Library's anchor stays honest through a compensated bar.
+test('a Library selection does not jump after a pending height correction', async ({ page, request }) => {
+    await page.setViewportSize({ width: 1000, height: 800 });
+    await openLibrary(page, request);
+    await scrollToY(page, 3000);
+    const card = await cardBelow(promptCards(page), 250);
+    await card.locator('.image-overlays input[type="checkbox"]').check();
+    await expect(libraryBar(page)).toBeVisible();
+    const before = (await box(card)).top;
+    await page.setViewportSize({ width: 1300, height: 800 });
+    await expect(card).toBeAttached();
+    await page.setViewportSize({ width: 1000, height: 800 });
+    await expect.poll(async () => Math.abs((await box(card)).top - before)).toBeLessThanOrEqual(1);
+});
+
+// #531: after a bulk action on a bar, the page shows the refreshed list from the top.
+async function selectFarDownImages(page, request) {
+    await openImages(page, request);
+    await scrollToY(page, 1500);
+    await (await cardBelow(imageCards(page), 200)).locator('.image-overlays input[type="checkbox"]').check();
+    await expect(imageBar(page)).toBeVisible();
+}
+const atTop = page => expect.poll(() => page.evaluate(() => scrollY)).toBe(0);
+const applyDialog = async (page, title, value) => {
+    const dialog = page.getByRole('dialog', { name: title, exact: true });
+    await dialog.locator('#action-input').fill(value);
+    await dialog.getByRole('button', { name: /^(Apply|Add)/ }).click();
+    await expect(dialog).toHaveCount(0);
+};
+test('Images: Set category returns to the top of the refreshed list', async ({ page, request }) => {
+    await selectFarDownImages(page, request);
+    const read = page.waitForRequest(item => item.url().includes('/prompt_manager/images/'));
+    await imageBar(page).getByRole('button', { name: 'Set category', exact: true }).click();
+    await applyDialog(page, 'Categorize selected images', 'Studio');
+    await read;
+    await atTop(page);
+    await expect(imageBar(page)).toHaveCount(0);
+    await expect(imageCards(page).first()).toBeInViewport();
+});
+test('Images: Add tags returns to the top of the refreshed list when its job ends', async ({ page, request }) => {
+    await selectFarDownImages(page, request);
+    await imageBar(page).getByRole('button', { name: 'Add tags', exact: true }).click();
+    await applyDialog(page, 'Tag selected images', 'sticky-tag');
+    await atTop(page);
+    await expect(imageBar(page)).toBeVisible();
+});
+test('Library: Set category and Add tags return to the top of the reloaded shelf', async ({ page, request }) => {
+    await openLibrary(page, request);
+    for (const [button, title, value] of [['Set category', 'Categorize selected prompts', 'Studio'], ['Add tags', 'Tag selected prompts', 'sticky']]) {
+        await scrollToY(page, 2000);
+        await (await cardBelow(promptCards(page), 250)).locator('.image-overlays input[type="checkbox"]').check();
+        await libraryBar(page).getByRole('button', { name: button, exact: true }).click();
+        await applyDialog(page, title, value);
+        await atTop(page);
+        await expect(libraryBar(page)).toHaveCount(0);
+        await expect(promptCards(page).first()).toBeInViewport();
+    }
+});
+test('Images: Delete… returns to the top of the reloaded list', async ({ page, request }) => {
+    await selectFarDownImages(page, request);
+    await imageBar(page).getByRole('button', { name: 'Delete…', exact: true }).click();
+    const dialog = page.locator('dialog[open]');
+    await dialog.getByRole('radio', { name: /^Remove from the library only/ }).check();
+    await dialog.locator('.dialog-actions button.danger').click();
+    await expect(toast(page)).toContainText('Removed 1 image from the library.');
+    await atTop(page);
+    await expect(page.locator('#bulkbar')).toBeEmpty();
+});
+test('Library: Delete… returns to the top of the reloaded shelf', async ({ page, request }) => {
+    await openLibrary(page, request);
+    await scrollToY(page, 2000);
+    await (await cardBelow(promptCards(page), 250)).locator('.image-overlays input[type="checkbox"]').check();
+    await libraryBar(page).getByRole('button', { name: 'Delete…', exact: true }).click();
+    await page.locator('dialog[open] .dialog-actions button.danger').click();
+    await expect(page.locator('dialog[open]')).toHaveCount(0);
+    await atTop(page);
+    await expect(page.locator('#library-bulkbar')).toBeEmpty();
+});
+
diff --git a/tests/js/workspace-images-selection.test.js b/tests/js/workspace-images-selection.test.js
index 0aa18166..4dd4715a 100644
--- a/tests/js/workspace-images-selection.test.js
+++ b/tests/js/workspace-images-selection.test.js
@@ -76,6 +76,9 @@ function fakeDOM() {
 
 /** The bar over `items` with `checked` keys; `options` adds the collection props. */
 function mountBar(dom, items, checkedKeys, options = {}) {
+    // The bar publishes its height for the sticky chrome (D186); nothing in this DOM ever resizes.
+    globalThis.ResizeObserver ??= class { observe() {} disconnect() {} };
+    document.documentElement ??= { style: { setProperty() {}, removeProperty() {} } };
     const scope = createScope();
     const grid = new dom.Element('div');
     const focusFallback = new dom.Element('h1');
diff --git a/tools/vendor/frontend-coverage-baseline.json b/tools/vendor/frontend-coverage-baseline.json
index ba112c10..eb695acc 100644
--- a/tools/vendor/frontend-coverage-baseline.json
+++ b/tools/vendor/frontend-coverage-baseline.json
@@ -718,5 +718,11 @@
     "branches": 95,
     "functions": 98,
     "statements": 97
+  },
+  "workspace/sticky-chrome.mjs": {
+    "lines": 80,
+    "branches": 60,
+    "functions": 80,
+    "statements": 80
   }
 }
diff --git a/web/js/workspace/images-collections.mjs b/web/js/workspace/images-collections.mjs
index 69806cae..5a9bb0b3 100644
--- a/web/js/workspace/images-collections.mjs
+++ b/web/js/workspace/images-collections.mjs
@@ -35,7 +35,7 @@ export function collectionTargets(images, { allMatching = false, total = images.
  * the dialog seam. A stale source (409) calls `onSourceChanged()` after its toast, so the page reloads the listing.
  */
 export function openAddToCollection({ scope, collections, images, trigger = null, allMatching = false, total = images.length,
-    notify = showWorkspaceToast, openInput = openInputDialog, onSourceChanged = null }) {
+    notify = showWorkspaceToast, openInput = openInputDialog, onSourceChanged = null, onAdded = null }) {
     const { targets, refusal } = collectionTargets(images, { allMatching, total });
     if (refusal) { notify(refusal); return; }
     openInput({ scope, trigger, title: ADD_DIALOG_TITLE, label: ADD_DIALOG_LABEL, action: ADD_DIALOG_ACTION,
@@ -45,7 +45,7 @@ export function openAddToCollection({ scope, collections, images, trigger = null
             if (name === null) { notify(ADD_FAILED_TOAST); return; }
             try {
                 const result = await collections.add({ name }, targets);
-                if (!scope.signal.aborted) notify(addedMessage(result));
+                if (!scope.signal.aborted) { notify(addedMessage(result)); onAdded?.(); }
             } catch (error) {
                 if (scope.signal.aborted) return;
                 notify(writeFailure(error, ADD_FAILED_TOAST));
diff --git a/web/js/workspace/images-selection.mjs b/web/js/workspace/images-selection.mjs
index b9c7c3ce..aed2ab12 100644
--- a/web/js/workspace/images-selection.mjs
+++ b/web/js/workspace/images-selection.mjs
@@ -1,3 +1,4 @@
+import { keepingPlace, publishBarHeight } from './sticky-chrome.mjs';
 import { createButton } from '../shared/toolkit/core.js';
 import { imageKey, toggleSelection, selectionLabel } from './images-state.mjs';
 import { inspectPath, toInspectionRecord } from './inspection-state.mjs';
@@ -51,7 +52,7 @@ function el(tag, text, className) {
  */
 export function mountSelectionBar({ scope, api, grid, getItems, focusFallback, onCategorySet, activity = null, onTagged,
     getListing, getFilter, getCategories, checked: initial = Object.freeze(new Set()), collections = null,
-    collection = null, onCollectionsChanged = null, onSourceChanged = null, onDeleted = null, removedView = null,
+    collection = null, onCollectionsChanged = null, onSourceChanged = null, onCollectionAdded = null, onDeleted = null, removedView = null,
     onReturn = null }) {
     let checked = initial;
     let exporting = false, categorizing = false;
@@ -59,6 +60,7 @@ export function mountSelectionBar({ scope, api, grid, getItems, focusFallback, o
     let anchor = null, allMatching = false, touchMode = false, lastPointer = 'mouse', shiftBox = null;
     const element = el('div');
     element.id = 'bulkbar';
+    publishBarHeight(scope, element);
     const bulk = el('div', undefined, 'bulkbar'), count = el('strong');
     const selectMatching = createButton('');
     scope.listen(selectMatching, 'click', () => {
@@ -87,7 +89,7 @@ export function mountSelectionBar({ scope, api, grid, getItems, focusFallback, o
     if (collections) {
         const addToCollection = createButton('Add to collection');
         scope.listen(addToCollection, 'click', () => openAddToCollection({ scope, collections, images: checkedImages(),
-            trigger: addToCollection, ...collectionSelection(), onSourceChanged }));
+            trigger: addToCollection, ...collectionSelection(), onSourceChanged, onAdded: onCollectionAdded }));
         bulk.append(addToCollection);
     }
     if (collections && collection) {
@@ -124,7 +126,8 @@ export function mountSelectionBar({ scope, api, grid, getItems, focusFallback, o
     }
 
     /** The count updates in place: the same bar and `strong`, its text written only when it changes. */
-    function render() {
+    function render() { keepingPlace(element, paintBar); }
+    function paintBar() {
         if (!checked.size && !allMatching) { touchMode = false; bulk.remove(); return; }
         paintMode();
         const listing = getListing();
diff --git a/web/js/workspace/images.mjs b/web/js/workspace/images.mjs
index 354a7895..1527d623 100644
--- a/web/js/workspace/images.mjs
+++ b/web/js/workspace/images.mjs
@@ -5,6 +5,7 @@ import { layoutImages, visibleImages, gridMetrics, stacksCardInfo } from './imag
 import { mountFileInspector } from './file-inspector.mjs';
 import { createInspectionController } from './inspection-state.mjs';
 import { mountSelectionBar } from './images-selection.mjs';
+import { scrollToPageTop } from './sticky-chrome.mjs';
 import { createPromptSender } from './prompt-sender.mjs';
 import { promptRoles } from './prompt-blocks.mjs';
 import { createWorkspaceIcon } from './icons.mjs';
@@ -301,6 +302,7 @@ export function mountImages(main, api, parentScope, {embedded = false, fetchPage
     collection.append(continuation);
     // After a Load more or Retry press, the index of the first image that batch appends (concept: focus it).
     let focusAfterLoad = null;
+    let panelHold = false;
     // The concept's side panel (app.js a426, D20); the Library-embedded gallery has its own page around it.
     const details = el('aside', undefined, 'detail-panel');
     if (!embedded) details.id = 'image-inspector';
@@ -310,11 +312,13 @@ export function mountImages(main, api, parentScope, {embedded = false, fetchPage
     // The checked cards and the concept's selection bar (#249 D8), between the filter row and the gallery layout. The
     // selection is kept across appended batches and cleared with the collection; the Library-embedded gallery has none.
     const bar = embedded ? null : mountSelectionBar({scope, api, grid, getItems:() => state?.items ?? [], focusFallback,
-        checked:visit?.checked, onCategorySet:() => { loadCategories(); reset(); }, activity, onTagged:keys => refreshTagged(keys),
-        onDeleted:deleted,
+        checked:visit?.checked, onCategorySet:() => { loadCategories(); reset(); scrollToPageTop(); }, activity,
+        // #531: a finished bulk action shows its result from the top. Tagging and collections keep the selection (D85, D138).
+        onTagged:keys => { refreshTagged(keys); bulkRefreshed(); },
+        onDeleted:() => { deleted(); scrollToPageTop(); },
         // #498: the removed view's bar holds only Return to library and Clear.
         removedView:() => filters.removed,
-        onReturn:(images, extra, trigger) => returnSome({images, ...extra, trigger}),
+        onReturn:(images, extra, trigger) => returnSome({images, ...extra, trigger, onDone:scrollToPageTop}),
         // The Set category field suggests the toolbar's categories (#332 MC13).
         getCategories:() => categoryNames,
         // #392 "Select all N matching": the listing's total and its filter, as the server lists them.
@@ -325,7 +329,7 @@ export function mountImages(main, api, parentScope, {embedded = false, fetchPage
             return filter.root !== undefined && typeof scope === 'string' ? {...filter, root_scope:scope} : filter;
         },
         // #331 D138: Add to collection, and Remove from collection on an open collection, which then lists it again.
-        collections, collection:filters.collection || null, onCollectionsChanged:collectionChanged,
+        collections, collection:filters.collection || null, onCollectionsChanged:() => { collectionChanged(); scrollToPageTop(); }, onCollectionAdded:bulkRefreshed,
         onSourceChanged:refreshInspectionCollection});
     if (bar) main.append(bar.element);
     main.append(body);
@@ -402,7 +406,10 @@ export function mountImages(main, api, parentScope, {embedded = false, fetchPage
         if (event.target.closest('.star-button')) toggleFavorite(api, image);
         else if (event.target.closest('.image-open')) previewImage(image);
         else if (action && !openCardTagging({api, scope, image, action, embedded, onSourceChanged:recovery.recover,
-            onRefresh:refreshInspectionCollection})) inspect(image);
+            onRefresh:refreshInspectionCollection})) {
+            inspect(image);
+            bringPanelIntoView();
+        }
     });
 
     function renderVisible() {
@@ -637,7 +644,19 @@ export function mountImages(main, api, parentScope, {embedded = false, fetchPage
     }
     scope.listen(more, 'click', pressLoad);
     scope.listen(retry, 'click', () => (state?.error?.code === 'cursor-stale' ? refreshInspectionCollection() : pressLoad()));
+    /**
+     * D189: at one column the panel follows the whole list, so Info goes to it. That passes the continuation, so loading
+     * waits for the reader's next move: a batch appended now would push the panel away.
+     */
+    function bringPanelIntoView() {
+        if (getComputedStyle(details).position !== 'static') return;
+        panelHold = true;
+        details.scrollIntoView({ block: 'start' });
+    }
+    const releasePanel = () => { if (panelHold) { panelHold = false; scheduleLoad(); } };
+    for (const name of ['wheel', 'touchmove', 'keydown']) scope.listen(window, name, releasePanel, { passive: true });
     function maybeLoad() {
+        if (panelHold) return;
         if (!observer || recovering || scope.signal.aborted || !state?.hasMore || state.loading || state.error || main.querySelector('#viewer-dialog[open]')) return;
         const bounds = continuation.getBoundingClientRect();
         if (bounds.top <= window.innerHeight + 250 && bounds.bottom >= 0) stream.loadMore();
@@ -702,8 +721,8 @@ export function mountImages(main, api, parentScope, {embedded = false, fetchPage
         else if (!showRemoved.isConnected) heading.actions.prepend(showRemoved);
     }
     /** #498: Return to library for the checked images, "all N matching" (`filter`) or the inspector's one. */
-    function returnSome({images = [], filter = null, count = images.length, trigger = null}) {
-        return returnImages({api, scope, store:activity, images, filter, count, trigger, onReturned:() => { if (!scope.signal.aborted) reset(); }});
+    function returnSome({images = [], filter = null, count = images.length, trigger = null, onDone = null}) {
+        return returnImages({api, scope, store:activity, images, filter, count, trigger, onReturned:() => { if (!scope.signal.aborted) { reset(); onDone?.(); } }});
     }
     /** #480: Delete… for one file, from the inspector or the viewer (`after` closes the viewer first). */
     function deleteOne(target, trigger, after = null) {
@@ -819,6 +838,12 @@ export function mountImages(main, api, parentScope, {embedded = false, fetchPage
      * is read again in place, keeping the scroll and the checked files still listed. A failed re-read lists the page
      * again from its start, whose failure shows the usual Retry (or the deleted-collection page).
      */
+    /** #531: after a bulk action that keeps the selection: the listing re-read, shown from the top. */
+    function bulkRefreshed() {
+        if (scope.signal.aborted) return;
+        scrollToPageTop();
+        if (!recovering) stream.refresh().catch(() => { if (!scope.signal.aborted) reset(); });
+    }
     async function collectionChanged() {
         if (scope.signal.aborted || !filters.collection || recovering) return;
         try {
diff --git a/web/js/workspace/index.mjs b/web/js/workspace/index.mjs
index 88aaae47..43ca8dcc 100644
--- a/web/js/workspace/index.mjs
+++ b/web/js/workspace/index.mjs
@@ -4,6 +4,7 @@ import { routes, mountRouter, summarizeStats, routeTitle, loadNavCounts, navigat
     LIBRARY_WRITE_COUNTS, NAV_COUNT_ROUTES, FAVORITE_WRITE_COUNTS, FAVORITE_COUNT_DELAY_MS, REVIEW_WRITE_COUNTS,
     JOB_END_COUNTS } from './state.mjs';
 import { mountWorkspaceTheme } from './theme.mjs';
+import { mountBackToTop } from './sticky-chrome.mjs';
 import { forgetImagesVisit, mountImages, onFavoriteChange } from './images.mjs';
 import { forgetLibraryVisit, mountLibrary, mountNewPromptAction, onLibraryWrite } from './library.mjs';
 import { mountVocabulary } from './vocabulary.mjs';
@@ -83,6 +84,7 @@ function mountWorkspace() {
     // row's count and the Activity page, on every route.
     const activity = createActivityStore({ api, scope, connect: url => new EventSource(resolveUrl(url)) });
     mountActivityTopbar({ store: activity, scope });
+    mountBackToTop({ scope, toast: document.getElementById('workspace-toast') });
     activity.load();
     // D129: a node-folder library is offered a move (or "Keep it here") above every page.
     mountLibraryBanner(document.getElementById('library-banner'), { api, activity, scope });
diff --git a/web/js/workspace/library-selection.mjs b/web/js/workspace/library-selection.mjs
index b6bfb082..92e6f254 100644
--- a/web/js/workspace/library-selection.mjs
+++ b/web/js/workspace/library-selection.mjs
@@ -1,3 +1,4 @@
+import { keepingPlace, publishBarHeight } from './sticky-chrome.mjs';
 import { createButton } from '../shared/toolkit/core.js';
 import { selectionLabel, toggleSelection } from './images-state.mjs';
 import { applyKeys, rangeKeys } from './images-multiselect.mjs';
@@ -129,10 +130,11 @@ export function categoryProblem(value) {
  * to `focusFallback` when it was on the bar the reload hides.
  */
 export function mountLibrarySelection({ scope, api, grid, getItems, getEpoch, getCategories, focusFallback, onCommitted,
-    onReload, getShelf = () => 'active', nameOf = () => null }) {
+    onReload, getShelf = () => 'active', nameOf = () => null, onPlaceKept = () => {} }) {
     let checked = Object.freeze(new Set()), anchor = null, shiftBox = null, writing = false;
     const element = el('div');
     element.id = 'library-bulkbar';
+    publishBarHeight(scope, element);
     const bulk = el('div', undefined, 'bulkbar'), count = el('strong');
     const addTags = createButton('Add tags');
     const setCategory = createButton('Set category');
@@ -164,6 +166,10 @@ export function mountLibrarySelection({ scope, api, grid, getItems, getEpoch, ge
 
     const ids = () => getItems().map(item => item.id);
     function render() {
+        const shift = keepingPlace(element, paintBar);
+        if (shift) onPlaceKept(shift);
+    }
+    function paintBar() {
         if (!checked.size) { bulk.remove(); return; }
         const shelf = getShelf() === 'archived' ? 'archived' : 'active';
         if (shelf !== shownShelf) {
diff --git a/web/js/workspace/library.mjs b/web/js/workspace/library.mjs
index a7238296..164f49d7 100644
--- a/web/js/workspace/library.mjs
+++ b/web/js/workspace/library.mjs
@@ -16,6 +16,7 @@ import {mountToolbar} from './toolbar.mjs';
 import {libraryFilters,libraryViewState} from './saved-views.mjs';
 import {openRefineDialog,openContentDialog} from './workspace-dialogs.mjs';
 import {mountLibrarySelection} from './library-selection.mjs';
+import {scrollToPageTop} from './sticky-chrome.mjs';
 import {fallBackToOriginal,replaceOnError,showsThumbnail,thumbnailSource} from './thumbnail-support.mjs';
 import {COPY as DELETE_COPY,RESTORE_URL,archivedNoticeText,restoreOutcome,reviewPromptDelete} from './library-delete.mjs';
 import {createMoreMenu} from './more-menu.mjs';
@@ -190,10 +191,11 @@ export function mountLibrary(main,api,parentScope,{positiveId,savedState=null,on
         const grid=el('div',undefined,'library-grid');grid.setAttribute('role','list');grid.setAttribute('aria-label','Positive prompts');
         // #437 D148: select prompts and set their category (the legacy admin's Set Category); a write reloads the shelf.
         let categoryNames=[];
-        const selection=mountLibrarySelection({scope,api,grid,getItems:()=>state?.items ?? [],getEpoch:()=>state?.epoch ?? null,
+        // #531: the bar's compensating scroll is not the reader moving, so a pending anchor keeps its offset.
+        const selection=mountLibrarySelection({scope,api,grid,onPlaceKept:shift=>{observedScrollY+=shift;},getItems:()=>state?.items ?? [],getEpoch:()=>state?.epoch ?? null,
             getCategories:()=>categoryNames,focusFallback:{focus:()=>focusHeading(main)},getShelf:()=>filters.shelf,
             nameOf:id=>{const item=state?.items.find(entry=>entry.id===id);return item?displayTitle(item):null;},
-            onCommitted:(kind,receipt)=>invalidateLibraryAfterWrite({kind:`bulk-${kind}`,receipt}),onReload:()=>{loadCategories();reset();}});
+            onCommitted:(kind,receipt)=>invalidateLibraryAfterWrite({kind:`bulk-${kind}`,receipt}),onReload:()=>{loadCategories();reset();scrollToPageTop();}});
         const message=el('p','','library-status');message.setAttribute('role','status');
         const continuation=el('div',undefined,'library-continuation');
         const more=createButton('Load more prompts');const retry=createButton('Retry prompt library');retry.hidden=true;
diff --git a/web/js/workspace/review.mjs b/web/js/workspace/review.mjs
index 22fa9d25..ac959a06 100644
--- a/web/js/workspace/review.mjs
+++ b/web/js/workspace/review.mjs
@@ -314,6 +314,8 @@ export function mountReview(main, { api, scope, onDecision = () => {}, onTotal,
         }
         // Info selects the item, as the concept's `inspect` does on this page (app.js a1244–1248).
         controller.select(item.id);
+        // D189: at one column the panel cannot stay beside the queue, so Info brings it into view.
+        if (getComputedStyle(panel).position === 'static') panel.scrollIntoView({ block: 'nearest' });
     });
 
     let shownTotal = null;
diff --git a/web/js/workspace/sticky-chrome.mjs b/web/js/workspace/sticky-chrome.mjs
new file mode 100644
index 00000000..c95146ad
--- /dev/null
+++ b/web/js/workspace/sticky-chrome.mjs
@@ -0,0 +1,91 @@
+/**
+ * The chrome that stays with you as a page scrolls (#531, beyond the concept; TESTING.md D186 and D187).
+ *
+ * - `keepingPlace`: repaint a sticky selection bar without moving the cards under the pointer.
+ * - `publishBarHeight`: tell the root how much of the viewport's top a shown bar takes, for the Images panel's sticky
+ *   offset and for `scroll-margin` (a focused card is not left under the bar).
+ * - `mountBackToTop`: the shell's chip, which rests above the toast's spot and rises only for a taller toast.
+ */
+
+/** How far off the top of the page the chip appears, in CSS pixels. */
+export const BACK_TO_TOP_AFTER = 200;
+/** The gap between the stuck bar and whatever it clears (its `inset-block-start` above, and as much below). */
+const BAR_GAP = 16;
+const TOAST_GAP = 8;
+
+/**
+ * Run `paint`, which may change the height of `element`. While the element's place in the page's flow is above the
+ * viewport (the bar is stuck), scroll by the difference, so the content below stays where it was. On screen, the bar
+ * pushes the content as the concept's does. Native scroll anchoring would add its own correction in some browsers, so
+ * it is off until the next frame. Returns the distance scrolled.
+ */
+export function keepingPlace(element, paint) {
+    const next = element.nextElementSibling;
+    if (!next || !element.isConnected) { paint(); return 0; }
+    const before = next.getBoundingClientRect().top;
+    const root = document.documentElement;
+    const anchoring = root.style.overflowAnchor;
+    root.style.overflowAnchor = 'none';
+    paint();
+    const shift = next.getBoundingClientRect().top - before;
+    requestAnimationFrame(() => { root.style.overflowAnchor = anchoring; });
+    if (!shift || before >= Math.max(0, element.getBoundingClientRect().bottom)) return 0;
+    const from = window.scrollY;
+    window.scrollBy({ top: shift, behavior: 'instant' });
+    return window.scrollY - from;
+}
+
+/** Publish the height of the bar inside `element` as `--selection-bar-block` while it shows; cleared with `scope`. */
+export function publishBarHeight(scope, element) {
+    const root = document.documentElement;
+    const clear = () => root.style.removeProperty('--selection-bar-block');
+    const update = () => {
+        const height = element.getBoundingClientRect().height;
+        if (height > 0) root.style.setProperty('--selection-bar-block', `${height + BAR_GAP}px`);
+        else clear();
+    };
+    const observer = new ResizeObserver(update);
+    observer.observe(element);
+    scope.cleanup(() => { observer.disconnect(); clear(); });
+}
+
+/** Go to the top of the page at once: the pages' own height corrections would cancel a smooth scroll part way. */
+export function scrollToPageTop() {
+    window.scrollTo({ top: 0, behavior: 'instant' });
+}
+
+/** One chip for the whole shell: shown off the top of any page; pressing it goes to the top at once. */
+export function mountBackToTop({ scope, toast }) {
+    const button = document.createElement('button');
+    button.type = 'button';
+    button.className = 'back-to-top';
+    button.hidden = true;
+    const arrow = document.createElement('span');
+    arrow.setAttribute('aria-hidden', 'true');
+    arrow.textContent = '↑';
+    button.append(arrow, ' Back to top');
+    toast.after(button);
+
+    // Scroll events already come once a frame, and this only reads `scrollY`.
+    const update = () => { button.hidden = window.scrollY <= BACK_TO_TOP_AFTER; };
+    scope.listen(window, 'scroll', update, { passive: true });
+    scope.listen(button, 'click', () => {
+        // Never animated, so reduced motion holds. The chip hides under the focus, so focus moves to the page.
+        scrollToPageTop();
+        document.getElementById('workspace-main')?.focus({ preventScroll: true });
+        update();
+    });
+
+    const root = document.documentElement;
+    const followToast = () => {
+        const height = toast.getBoundingClientRect().height;
+        if (height > 0) root.style.setProperty('--toast-block', `${height + TOAST_GAP}px`);
+        else root.style.removeProperty('--toast-block');
+    };
+    const toastObserver = new MutationObserver(followToast);
+    toastObserver.observe(toast, { childList: true, characterData: true, subtree: true });
+    scope.listen(window, 'resize', followToast);
+    scope.cleanup(() => { toastObserver.disconnect(); root.style.removeProperty('--toast-block'); button.remove(); });
+    update();
+    return button;
+}
diff --git a/web/js/workspace/workspace.css b/web/js/workspace/workspace.css
index 50892095..c5ec0ec9 100644
--- a/web/js/workspace/workspace.css
+++ b/web/js/workspace/workspace.css
@@ -290,7 +290,7 @@ main:focus-visible { outline: 2px solid var(--ca-focus); outline-offset: 4px; }
 }
 /* #249 D42: a discovery alert a rescan leaves scrolls clear of the concept's fixed toast (22px inset, 12px at 700px and
    below, two 12px lines at 390px), never under it; the toast itself keeps the concept's placement. */
-.options-status { font-size: 12px; padding-inline: 4px; scroll-margin-block-end: 96px; /* D42 */ }
+.options-status { font-size: 12px; padding-inline: 4px; scroll-margin-block-end: 140px; /* D42, D187: clear of the toast and the chip above it */ }
 
 /* Prompt library cards (#249 PR E): the concept's `article.prompt-card` (s653–708) with real prompts, titles and media. */
 /* #249 D23: real prompts are far longer than the concept's samples, so the card clamps the positive to two lines; copy
@@ -542,3 +542,34 @@ pre.prompt-text { font: inherit; font-size: 12px; line-height: 1.75; margin-bloc
         overflow: hidden; overflow-wrap: anywhere;
     }
 }
+
+/* D186 (#531, beyond the concept): the selection bars stay in view while you select. This one rule is their position. `--selection-bar-block`
+   (sticky-chrome.mjs) is the room a shown bar takes; a focused card control and the Images panel keep clear of it
+   (scroll-margin on them, not scroll-padding on the root, which would scroll the page to reveal the bar's own buttons). At one
+   column the bar is one row that scrolls sideways, so it does not take a fifth of a phone screen. */
+#bulkbar, #library-bulkbar { position: sticky; inset-block-start: 8px; z-index: 5; }
+:is(#image-grid, .library-grid) :is(article, a, button, input, select, textarea, [tabindex]) { scroll-margin-block-start: var(--selection-bar-block, 0px); }
+.detail-panel { inset-block-start: max(20px, var(--selection-bar-block, 0px)); max-block-size: calc(100dvh - 20px - max(20px, var(--selection-bar-block, 0px))); /* D186 */ }
+@media (max-width: 700px) {
+    .detail-panel { max-block-size: none; /* D186 */ }
+    .bulkbar { flex-wrap: nowrap; overflow-x: auto; scrollbar-width: thin; /* D186 */ }
+    .bulkbar > * { flex: none; /* D186 */ }
+}
+@container images-page (inline-size < 600px) { .detail-panel { max-block-size: none; /* D186 */ } }
+
+/* D187 (#531, beyond the concept): Back to top, in the toast's column. It rests above a two-line toast, so the usual
+   toast does not move it under a finger, and rises only for a taller one. */
+.ca-tools .back-to-top {
+    --toast-rest: 70px;
+    position: fixed; inset-inline-start: 50%; transform: translateX(-50%); z-index: 10;
+    inset-block-end: calc(22px + max(var(--toast-rest), var(--toast-block, 0px)));
+    padding: 6px 12px; border: 1px solid var(--ca-line); border-radius: 999px; background: var(--ca-surface);
+    box-shadow: 0 8px 35px #0004; font-size: 12px; white-space: nowrap;
+}
+@media (max-width: 700px) { .ca-tools .back-to-top { inset-block-end: calc(12px + max(var(--toast-rest), var(--toast-block, 0px))); } }
+@media (pointer: coarse) { .ca-tools .back-to-top { min-block-size: 40px; } }
+
+/* D188 (#531, beyond the concept): the Resolve panel stays with you as the Images panel does. */
+.review-panel { position: sticky; inset-block-start: 20px; }
+@media (max-width: 700px) { .review-panel { position: static; } }
+@media (min-width: 701px) and (max-height: 720px) { .review-panel { max-block-size: calc(100dvh - 40px); overflow: auto; } }