[DevTools] Fix WhatChanged scrolling out of view in profiler sidebar

packages/react-devtools-shared/src/devtools/views/Components/InspectedElementBadges.css

@@ -1,8 +1,9 @@
 .Root {
   user-select: none;
-  display: inline-flex;
-}
-
-.Root *:not(:first-child) {
-  margin-left: 0.25rem;
+  flex: 1 1 auto; 
+  min-width: 0;
+  display: flex;
+  flex-wrap: wrap;
+  justify-content: start;
+  gap: 0.25rem;
 }

packages/react-devtools-shared/src/devtools/views/Profiler/SidebarSelectedFiberInfo.css

@@ -7,10 +7,13 @@
   border-bottom: 1px solid var(--color-border);
 }
 
+.CurrentRenderInfo strong {
+  color: var(--color-text-primary);
+}
+
 .Content {
-  padding: 0.5rem;
+  padding: 0 0.5rem 0.5rem;
   user-select: none;
-  overflow-y: auto;
   display: flex;
   flex-direction: column;
   gap: 0.5rem;

packages/react-devtools-shared/src/devtools/views/Profiler/SidebarSelectedFiberInfo.js

@@ -19,6 +19,7 @@ import ButtonIcon from '../ButtonIcon';
 import InspectedElementBadges from '../Components/InspectedElementBadges';
 
 import styles from './SidebarSelectedFiberInfo.css';
+import StickyCollapsibleHeader from './StickyCollapsibleHeader';
 
 export default function SidebarSelectedFiberInfo(): React.Node {
   const {profilerStore} = useContext(StoreContext);
@@ -114,6 +115,18 @@ export default function SidebarSelectedFiberInfo(): React.Node {
     );
   }
 
+  let selectedCommitTime = 0;
+  let selectedCommitDuration = 0;
+
+  if (selectedCommitIndex !== null && rootID !== null) {
+    const commitData = profilerStore.getCommitData(
+      ((rootID: any): number),
+      selectedCommitIndex,
+    );
+    selectedCommitTime = commitData.timestamp;
+    selectedCommitDuration = commitData.duration;
+  }
+
   return (
     <Fragment>
       <div className={styles.Toolbar}>
@@ -127,14 +140,24 @@ export default function SidebarSelectedFiberInfo(): React.Node {
           <ButtonIcon type="close" />
         </Button>
       </div>
-      <div className={styles.Content} onKeyDown={handleKeyDown} tabIndex={0}>
-        {node != null && (
-          <InspectedElementBadges
-            hocDisplayNames={node.hocDisplayNames}
-            compiledWithForget={node.compiledWithForget}
-          />
-        )}
-        <WhatChanged fiberID={((selectedFiberID: any): number)} />
+      <div className={styles.Content} onKeyDown={handleKeyDown}>
+        <StickyCollapsibleHeader
+          summary={
+            <span className={styles.CurrentRenderInfo}>
+              <strong>
+                {formatTime(selectedCommitTime)}s for{' '}
+                {formatDuration(selectedCommitDuration)}ms
+              </strong>
+            </span>
+          }>
+          {node != null && (
+            <InspectedElementBadges
+              hocDisplayNames={node.hocDisplayNames}
+              compiledWithForget={node.compiledWithForget}
+            />
+          )}
+          <WhatChanged fiberID={((selectedFiberID: any): number)} />
+        </StickyCollapsibleHeader>
         {listItems.length > 0 && (
           <div>
             <label className={styles.Label}>Rendered at: </label>

packages/react-devtools-shared/src/devtools/views/Profiler/StickyCollapsibleHeader.css

@@ -0,0 +1,55 @@
+.StickyHeader {
+  position: sticky;
+  top: 0;
+  z-index: 1;
+  display: flex;
+  flex-direction: column;
+  gap: 0.5rem;
+  padding: 0.5rem 0;
+  background: var(--color-background);
+}
+
+.StickyHeader::after {
+  content: "";
+  position: absolute;
+  inset-inline: -0.5rem;
+  bottom: 0;
+  height: 1px;
+  background: var(--color-border);
+}
+
+.HeaderRow {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  gap: 0.5rem;
+  cursor: pointer;
+  user-select: none;
+  border-radius: 4px;
+  padding: 0.25rem 0;
+}
+
+.HeaderRow:hover .RenderSummary {
+  text-decoration: underline;
+}
+
+.HeaderRow:focus-visible {
+  background: var(--color-button-background-focus);
+  outline: none;
+}
+
+.HeaderRowControls {
+  flex: 0 0 auto;
+}
+
+.RenderSummary {
+  flex: 1;
+  min-width: 0;
+  color: var(--color-text-secondary);
+}
+
+.CollapsibleContent {
+  display: flex;
+  flex-direction: column;
+  gap: 0.75rem;
+}

packages/react-devtools-shared/src/devtools/views/Profiler/StickyCollapsibleHeader.js

@@ -0,0 +1,63 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+import * as React from 'react';
+import {useState} from 'react';
+
+import ButtonIcon from '../ButtonIcon';
+
+import styles from './StickyCollapsibleHeader.css';
+
+type Props = {
+  summary: React.Node,
+  children: React.Node,
+};
+
+export default function StickyCollapsibleHeader({
+  summary,
+  children,
+}: Props): React.Node {
+  const [isCollapsed, setIsCollapsed] = useState(false);
+
+  const toggleCollapsedVal = () =>
+    setIsCollapsed(prevIsCollapsed => !prevIsCollapsed);
+
+  // $FlowFixMe[missing-local-annot]
+  const handleKeyDown = event => {
+    if (event.key === 'Enter' || event.key === ' ') {
+      // Prevent the browser from scrolling down when Space is pressed
+      if (event.key === ' ') {
+        event.preventDefault();
+      }
+      toggleCollapsedVal();
+    }
+  };
+
+  return (
+    <div className={styles.StickyHeader}>
+      <div
+        className={styles.HeaderRow}
+        onClick={toggleCollapsedVal}
+        tabIndex={0}
+        role="button"
+        aria-expanded={!isCollapsed}
+        onKeyDown={handleKeyDown}>
+        <div className={styles.RenderSummary}>{summary}</div>
+
+        <div className={styles.HeaderRowControls}>
+          <ButtonIcon type={isCollapsed ? 'expanded' : 'collapsed'} />
+        </div>
+      </div>
+
+      {!isCollapsed && (
+        <div className={styles.CollapsibleContent}>{children}</div>
+      )}
+    </div>
+  );
+}