diff --git a/package.json b/package.json
index 555fa95a..4e56b13c 100644
--- a/package.json
+++ b/package.json
@@ -32,6 +32,7 @@
     "test:bridge": "node test/bridge.js",
     "test:outlines": "node test/outlines.js",
     "test:navigator": "node test/navigator.js",
+    "test:navigatoropencode": "node test/navigator-open-code.js",
     "test:classattr": "node test/class-attr.js",
     "test:gridtracks": "node test/grid-tracks.js",
     "test:windowbounds": "node test/window-bounds.js",
diff --git a/src/App.tsx b/src/App.tsx
index 07c1a1b3..094eda14 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -100,6 +100,12 @@ import { toRecord } from '../shared/record';
 import { projectRelativePath } from './projectPath.js';
 import { currentDesktopPlatform, shortcutLabel } from './shortcutLabel.js';
 import { sourceNodeAtOffset } from './codePanelModel.js'
+import {
+  codeWindowFor,
+  FRONTMATTER_SUBJECT,
+  type CodeSubject,
+  type FrontmatterSubject,
+} from './codeWindowTarget';
 import {
   cloneEditorModel,
   findEditorNodeById as findNodeById,
@@ -3592,7 +3598,7 @@ export default function App() {
   };
 
   const selectedNode:
-    | EditorNode | { readonly id: 'frontmatter'; readonly kind: 'frontmatter'; readonly value: string } | null =
+    | EditorNode | (FrontmatterSubject & { readonly value: string }) | null =
     model && selectedId
       ? selectedId === 'frontmatter'
         ? { id: 'frontmatter', kind: 'frontmatter', value: frontmatterCode }
@@ -3944,29 +3950,22 @@ export default function App() {
     ? codeWinNode.inner
     : null;
 
-  // Returns whether the selection actually has a code editor, so the Enter
+  // Returns whether the subject actually has a code editor, so the Enter
   // shortcut below knows whether it handled the key.
-  const openCodeWindow = () => {
-    if (!selectedNode) {
+  const openCodeWindowFor = (subject: CodeSubject | null): boolean => {
+    const codeWindow = subject === null ? undefined : codeWindowFor(subject);
+    if (codeWindow === undefined) {
       return false;
     }
-    if (selectedNode.kind === 'frontmatter') {
-      setCodeWin({
-        targetId: 'frontmatter',
-        title: 'Frontmatter',
-        language: 'javascript',
-      });
-      return true;
-    }
-    if (selectedNode.kind === 'raw') {
-      setCodeWin({
-        targetId: selectedNode.id,
-        title: `<${selectedNode.name}>`,
-        language: selectedNode.name === 'style' ? 'css' : 'javascript',
-      });
-      return true;
-    }
-    return false;
+    setCodeWin(codeWindow);
+    return true;
+  };
+  const openCodeWindow = (): boolean => openCodeWindowFor(selectedNode);
+  // A navigator double-click names its row instead of reading `selectedNode`
+  // (see `openCode` in StructureTree). An id the tree no longer holds, a row
+  // removed between the click and the render, opens nothing.
+  const openCodeWindowById = (id: string): void => {
+    openCodeWindowFor(id === 'frontmatter' ? FRONTMATTER_SUBJECT : tree.node(id));
   };
   // Read by the keydown effect, which is set up long before this exists.
   openCodeWindowRef.current = openCodeWindow;
@@ -4619,6 +4618,7 @@ export default function App() {
                 onSelect={setSelectedId}
                 onHoverNode={setHoverNodeId}
                 onOpenComponent={(name, id) => openComponent(name, pathFor(id))}
+                onOpenCode={openCodeWindowById}
                 onChangeLayout={changeLayout}
                 onDropComponent={addComponent}
                 onMoveNode={moveNode}
diff --git a/src/codeWindowTarget.ts b/src/codeWindowTarget.ts
new file mode 100644
index 00000000..5317c476
--- /dev/null
+++ b/src/codeWindowTarget.ts
@@ -0,0 +1,38 @@
+import { assert } from '../shared/assert';
+import type { CodeWindowState, EditorNode } from './appTypes';
+
+/** The page frontmatter: selectable like a node, but it is not one. */
+export interface FrontmatterSubject {
+  readonly id: 'frontmatter';
+  readonly kind: 'frontmatter';
+}
+
+export type CodeSubject = EditorNode | FrontmatterSubject;
+
+export const FRONTMATTER_SUBJECT: FrontmatterSubject = { id: 'frontmatter', kind: 'frontmatter' };
+
+// What the floating code editor opens for a subject. Enter, the "Edit code"
+// button and a navigator double-click all ask this one rule, so they cannot
+// disagree on the title or the language. Markup has no editor of its own: the
+// answer is `undefined`, and Enter is left unhandled.
+export function codeWindowFor(subject: CodeSubject): CodeWindowState | undefined {
+  if (subject.kind === 'frontmatter') {
+    return { targetId: 'frontmatter', title: 'Frontmatter', language: 'javascript' };
+  }
+  if (subject.kind === 'raw') {
+    assert(subject.id.length > 0, 'raw node has an id');
+    // The parser matches the tag case-insensitively but keeps it as written,
+    // so `<STYLE>` arrives here as "STYLE".
+    const language = RAW_CODE_LANGUAGES[subject.name.toLowerCase()];
+    assert(language !== undefined, `raw node <${subject.name}> has no code language`);
+    return { targetId: subject.id, title: `<${subject.name}>`, language };
+  }
+  return undefined;
+}
+
+// The parser keeps exactly these elements raw (`RAW_ELEMENTS` in
+// electron/astroParser.ts), so they are the only ones with a code language.
+const RAW_CODE_LANGUAGES: Readonly<Record<string, string>> = {
+  script: 'javascript',
+  style: 'css',
+};
diff --git a/src/panels/StructurePanel.tsx b/src/panels/StructurePanel.tsx
index f07c62ef..4b3fa0ed 100644
--- a/src/panels/StructurePanel.tsx
+++ b/src/panels/StructurePanel.tsx
@@ -34,6 +34,8 @@ interface StructurePanelProps {
   readonly onSelect: (id: string) => void;
   readonly onHoverNode?: (id: string | null) => void;
   readonly onOpenComponent?: (name: string, id: string) => void;
+  /** A row holding code (frontmatter, <style>, <script>) was double-clicked. */
+  readonly onOpenCode?: (id: string) => void;
   readonly onChangeLayout: (name: string) => void;
   readonly onDropComponent: (name: string, target: DropLocation) => void;
   readonly onMoveNode: (id: string, target: DropLocation) => void;
@@ -342,6 +344,7 @@ function treeContextOf(props: EditableProps, state: TreeState): StructureTreeCon
     onSelect: props.onSelect,
     ...(props.onHoverNode === undefined ? {} : { onHoverNode: props.onHoverNode }),
     ...(props.onOpenComponent === undefined ? {} : { onOpenComponent: props.onOpenComponent }),
+    ...(props.onOpenCode === undefined ? {} : { onOpenCode: props.onOpenCode }),
     toggleCollapse: (node) => {
       state.setToggled((previous) =>
         new Map(previous).set(node.id, !collapsedState(node, previous)),
@@ -445,6 +448,7 @@ function FrontmatterRow({ props }: { readonly props: EditableProps }) {
       className={`structure-node frontmatter-node ${props.selectedId === 'frontmatter' ? 'selected' : ''}`}
       style={{ paddingLeft: 6 }}
       onClick={() => props.onSelect('frontmatter')}
+      onDoubleClick={() => props.onOpenCode?.('frontmatter')}
     >
       <span className="drag-handle" style={{ visibility: 'hidden' }}>
         <DragIcon size={11} />
diff --git a/src/panels/StructureTree.tsx b/src/panels/StructureTree.tsx
index 329f31fc..ecd7876e 100644
--- a/src/panels/StructureTree.tsx
+++ b/src/panels/StructureTree.tsx
@@ -50,6 +50,7 @@ export interface StructureTreeContext {
   readonly onSelect: (id: string) => void;
   readonly onHoverNode?: (id: string | null) => void;
   readonly onOpenComponent?: (name: string, id: string) => void;
+  readonly onOpenCode?: (id: string) => void;
   readonly toggleCollapse: (node: NavigatorNode) => void;
   readonly openContextMenu: (left: number, top: number, nodeId: string) => void;
 }
@@ -194,6 +195,7 @@ function treeContextFromRow(props: TreeNodeProps): StructureTreeContext {
     onSelect: props.onSelect,
     ...(props.onHoverNode === undefined ? {} : { onHoverNode: props.onHoverNode }),
     ...(props.onOpenComponent === undefined ? {} : { onOpenComponent: props.onOpenComponent }),
+    ...(props.onOpenCode === undefined ? {} : { onOpenCode: props.onOpenCode }),
     toggleCollapse: props.toggleCollapse,
     openContextMenu: props.openContextMenu,
   };
@@ -323,7 +325,12 @@ function treeRowHandlers(props: TreeRowProps) {
       props.onSelect(node.id);
     },
     onDoubleClick: (event: React.MouseEvent<HTMLDivElement>): void => {
-      openComponent(event, props);
+      // A <script> or <style> is code, not markup: it opens in the code editor.
+      if (node.kind === 'raw') {
+        openCode(event, props);
+      } else {
+        openComponent(event, props);
+      }
     },
     onMouseEnter: (): void => props.onHoverNode?.(node.id),
     onMouseLeave: (): void => props.onHoverNode?.(null),
@@ -335,6 +342,16 @@ function treeRowHandlers(props: TreeRowProps) {
   };
 }
 
+// The row's own id is passed on: its click has only just asked for the
+// selection, which still names the previous row when the double-click lands.
+function openCode(event: React.MouseEvent<HTMLDivElement>, props: TreeRowProps): void {
+  if (!props.onOpenCode) {
+    return;
+  }
+  event.stopPropagation();
+  props.onOpenCode(props.node.id);
+}
+
 function openComponent(event: React.MouseEvent<HTMLDivElement>, props: TreeRowProps): void {
   const { node } = props;
   if (!props.component || (node.kind === 'component' && node.astroAsset)) {
diff --git a/test/navigator-open-code.js b/test/navigator-open-code.js
new file mode 100644
index 00000000..4db50c67
--- /dev/null
+++ b/test/navigator-open-code.js
@@ -0,0 +1,169 @@
+// Goal: a double-click on a navigator row that holds code opens that code in the
+// floating editor — the one Enter and the "Edit code" button already open.
+//
+// Methodology: two layers, each checked on its own.
+// 1. `codeWindowFor`, the pure rule shared by Enter, the button and the
+//    double-click: which subject opens which editor, and what has none.
+// 2. The navigator itself, rendered in JSDOM: a double-click on the Frontmatter,
+//    a <style> or a <script> row reports that row's id — not the selection,
+//    which the row's own click has only just asked for — while element and
+//    component rows keep the behaviour they had.
+//
+//   node test/navigator-open-code.js
+
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+const esbuild = require('esbuild');
+
+const buildDir = path.join(__dirname, '..', 'node_modules', '.stacki-test');
+const settle = (ms = 0) => new Promise((resolve) => setTimeout(resolve, ms));
+
+const bundle = async (entry, name) => {
+  const outfile = path.join(buildDir, name);
+  await esbuild.build({
+    entryPoints: [path.join(__dirname, '..', 'src', ...entry)],
+    outfile,
+    bundle: true,
+    format: 'cjs',
+    platform: 'node',
+    jsx: 'automatic',
+    external: ['react', 'react-dom', 'react/jsx-runtime'],
+    logLevel: 'silent',
+  });
+  return require(outfile);
+};
+
+const raw = (id, name) => ({ id, kind: 'raw', name, inner: 'a {}' });
+const element = (id, name, children = []) => ({
+  id,
+  kind: 'element',
+  name,
+  props: { class: id },
+  children,
+});
+const component = (id, name) => ({ id, kind: 'component', name, props: {}, children: [] });
+
+function checkCodeWindowRule({ codeWindowFor }) {
+  assert.deepEqual(codeWindowFor({ id: 'frontmatter', kind: 'frontmatter' }), {
+    targetId: 'frontmatter',
+    title: 'Frontmatter',
+    language: 'javascript',
+  });
+  assert.deepEqual(codeWindowFor(raw('s1', 'style')), {
+    targetId: 's1',
+    title: '<style>',
+    language: 'css',
+  });
+  assert.deepEqual(codeWindowFor(raw('j1', 'script')), {
+    targetId: 'j1',
+    title: '<script>',
+    language: 'javascript',
+  });
+  // The parser keeps a tag as written, so a capitalised one must still open.
+  assert.deepEqual(codeWindowFor(raw('s2', 'STYLE')), {
+    targetId: 's2',
+    title: '<STYLE>',
+    language: 'css',
+  });
+  // Markup has no code editor of its own: Enter on it must stay unhandled.
+  assert.equal(codeWindowFor(element('e1', 'div')), undefined);
+  assert.equal(codeWindowFor(component('c1', 'Card')), undefined);
+  // The parser only ever makes <style> and <script> raw. Any other name is a
+  // broken invariant, not a language to guess.
+  assert.throws(
+    () => codeWindowFor(raw('t1', 'template')),
+    /Assertion failed: raw node <template> has no code language/,
+  );
+  assert.throws(() => codeWindowFor(raw('', 'style')), /Assertion failed: raw node has an id/);
+}
+
+function installDom() {
+  const { JSDOM } = require('jsdom');
+  const dom = new JSDOM('<!doctype html><div id="root"></div>', { pretendToBeVisual: true });
+  global.window = dom.window;
+  global.document = dom.window.document;
+  global.navigator = dom.window.navigator;
+  global.Element = dom.window.Element;
+  global.HTMLElement = dom.window.HTMLElement;
+  global.Node = dom.window.Node;
+  global.IS_REACT_ACT_ENVIRONMENT = true;
+  dom.window.Element.prototype.scrollIntoView = function scrollIntoView() {};
+  return dom;
+}
+
+async function checkNavigator(StructurePanel) {
+  const dom = installDom();
+  const React = require('react');
+  const { act } = require('react');
+  const { createRoot } = require('react-dom/client');
+  const container = dom.window.document.getElementById('root');
+  const reactRoot = createRoot(container);
+  const opened = { code: [], component: [] };
+  const nodes = [
+    element('page', 'main', [raw('s1', 'style'), element('e1', 'div'), component('c1', 'Card')]),
+    raw('j1', 'script'),
+  ];
+  await act(async () => {
+    reactRoot.render(
+      React.createElement(StructurePanel, {
+        pageState: { editable: true, model: { nodes, imports: [] } },
+        layouts: [],
+        currentLayoutName: '',
+        selectedId: null,
+        onSelect: () => {},
+        onOpenCode: (id) => opened.code.push(id),
+        onOpenComponent: (name, id) => opened.component.push(`${name}:${id}`),
+        onChangeLayout: () => {},
+        onDropComponent: () => {},
+        onMoveNode: () => {},
+        onRemoveNode: () => {},
+        onCopyNode: () => {},
+        onDuplicateNode: () => {},
+        onPasteNode: () => {},
+        onRawChange: () => {},
+        hasClipboard: false,
+      }),
+    );
+    await settle(20);
+  });
+  // Everything starts collapsed; the header button opens it all.
+  await act(async () => {
+    container.querySelector('.panel-header button').click();
+    await settle(20);
+  });
+  const doubleClick = async (row) => {
+    assert.ok(row, 'the row to double-click is drawn');
+    opened.code.length = 0;
+    opened.component.length = 0;
+    await act(async () => {
+      row.dispatchEvent(new dom.window.MouseEvent('dblclick', { bubbles: true }));
+      await settle(10);
+    });
+    return { code: [...opened.code], component: [...opened.component] };
+  };
+  const rowFor = (id) => container.querySelector(`.structure-node[data-node-id="${id}"]`);
+
+  const frontmatter = await doubleClick(container.querySelector('.frontmatter-node'));
+  assert.deepEqual(frontmatter, { code: ['frontmatter'], component: [] });
+  assert.deepEqual(await doubleClick(rowFor('s1')), { code: ['s1'], component: [] });
+  assert.deepEqual(await doubleClick(rowFor('j1')), { code: ['j1'], component: [] });
+  // Rows without code keep what they did before: nothing, or open the component.
+  assert.deepEqual(await doubleClick(rowFor('e1')), { code: [], component: [] });
+  assert.deepEqual(await doubleClick(rowFor('c1')), { code: [], component: ['Card:c1'] });
+  await act(async () => reactRoot.unmount());
+}
+
+(async () => {
+  fs.mkdirSync(buildDir, { recursive: true });
+  checkCodeWindowRule(await bundle(['codeWindowTarget.ts'], 'code-window-target.cjs'));
+  const { default: StructurePanel } = await bundle(
+    ['panels', 'StructurePanel.tsx'],
+    'navigator-open-code.cjs',
+  );
+  await checkNavigator(StructurePanel);
+  console.log('navigator-open-code: all checks passed');
+})().catch((error) => {
+  console.error(error);
+  process.exit(1);
+});