Hand focus back to the globe canvas after a render failure

When the control that had focus is gone or cannot take it, focus went to
the #cesiumContainer div, where Enter no longer finished a drawing. It now
goes to the globe's canvas, which the map's keys read as the map; the canvas
is focusable only until focus moves on or the globe is pressed. A control
disabled while the notice was up no longer leaves focus on the page, and
neither focus call scrolls.

docs/CURRENT-STATE.md

@@ -2225,9 +2225,12 @@ black globe behind controls that still respond. `installRenderFailureNotice()`
 Cesium stops its render loop, and for the canvas' `webglcontextlost`. It logs
 the error and publishes a notice to the status store, which
 `RenderFailure.vue` renders as an alert dialog that takes focus. When the
-globe draws again, focus goes back to the element that had it, or to the map
-(`#cesiumContainer`, made focusable with `tabindex="-1"`) if that element is
-gone, unless the user has moved focus since. The
+globe draws again, focus goes back to the element that had it, or, if that
+element is gone or cannot take focus, to the globe's canvas, which the map's
+keys (Enter to finish a drawing, Space to talk) read as the map. The canvas
+gets `tabindex="-1"` only until focus moves on or the globe is pressed, and a
+press leaves focus on the page, as Cesium has it. Focus the user moved
+meanwhile stays put. The
 application scene creates its viewer with `showRenderLoopErrors: false`, so
 Cesium's own "Rendering has stopped" panel, which offers no way back, no longer
 appears; `applicationViewerOptions()` and `createApplicationViewer()` keep

src/annotations/drawToolBehaviour.test.mjs

@@ -68,9 +68,17 @@ class FakeElement {
   }
   closest(selector) {
     // Only what the tool asks: "am I inside an activatable control?"
-    const activatable = ['button', 'a', 'select', '[role="button"]', '[role="radio"]'];
+    const activatable = [
+      'button',
+      'a',
+      'select',
+      '[role="button"]',
+      '[role="radio"]',
+    ];
     if (!activatable.some((part) => selector.includes(part))) return null;
-    return this.tagName === 'BUTTON' || this.tagName === 'A' || this.tagName === 'SELECT'
+    return this.tagName === 'BUTTON' ||
+      this.tagName === 'A' ||
+      this.tagName === 'SELECT'
       ? this
       : null;
   }
@@ -175,7 +183,14 @@ function fakeViewer() {
 }
 
 function fakeAnnotations() {
-  const calls = { annotate: [], clear: 0, restyle: [], setHidden: [], frame: [], remove: [] };
+  const calls = {
+    annotate: [],
+    clear: 0,
+    restyle: [],
+    setHidden: [],
+    frame: [],
+    remove: [],
+  };
   const marks = [];
   const listeners = new Set();
   const changed = () => listeners.forEach((listener) => listener());
@@ -300,7 +315,11 @@ test('Draw refuses to start when something else holds the pointer', async () =>
       h.shown.view.hint,
       'Directions is using the pointer — close it first.',
     );
-    assert.equal(h.tool.diagnostics().sceneHandler, false, 'no handler was bound');
+    assert.equal(
+      h.tool.diagnostics().sceneHandler,
+      false,
+      'no handler was bound',
+    );
 
     releasePointer(other);
     h.act('toggleDraw');
@@ -342,7 +361,10 @@ test('both stock viewer click actions are borrowed for the session and given bac
     const stockClick = () => 'viewer picks and selects';
     const stockDouble = () => 'viewer tracks';
     h.viewer.screenSpaceEventHandler.setInputAction(stockClick, LEFT_CLICK);
-    h.viewer.screenSpaceEventHandler.setInputAction(stockDouble, LEFT_DOUBLE_CLICK);
+    h.viewer.screenSpaceEventHandler.setInputAction(
+      stockDouble,
+      LEFT_DOUBLE_CLICK,
+    );
 
     h.act('toggleDraw');
     assert.equal(
@@ -380,20 +402,61 @@ test('Enter finishes from the canvas and the label field, never from a focused b
     h.tool.addVertex(-97.74, 30.27);
 
     // Enter while the Clear button has keyboard focus means "press Clear".
-    h.documentDouble.emit('keydown', { key: 'Enter', target: h.element('draw-clear') });
+    h.documentDouble.emit('keydown', {
+      key: 'Enter',
+      target: h.element('draw-clear'),
+    });
     await Promise.resolve();
     assert.equal(
       h.annotations.calls.annotate.length,
       0,
       'a focused button keeps its own Enter',
     );
-    assert.equal(h.tool.session.vertices.length, 3, 'and the shape is untouched');
+    assert.equal(
+      h.tool.session.vertices.length,
+      3,
+      'and the shape is untouched',
+    );
 
     // Enter from the page body (the canvas has focus in practice) finishes it.
-    h.documentDouble.emit('keydown', { key: 'Enter', target: h.documentDouble.body });
+    h.documentDouble.emit('keydown', {
+      key: 'Enter',
+      target: h.documentDouble.body,
+    });
     await Promise.resolve();
     await Promise.resolve();
-    assert.equal(h.annotations.calls.annotate.length, 1, 'Enter on the map finishes');
+    assert.equal(
+      h.annotations.calls.annotate.length,
+      1,
+      'Enter on the map finishes',
+    );
+    assert.equal(h.annotations.calls.annotate[0].specs[0].type, 'area');
+  } finally {
+    h.restore();
+  }
+});
+
+test('Enter on the globe canvas finishes, as after the render failure notice hands focus back', async () => {
+  const h = harness();
+  try {
+    h.act('toggleDraw');
+    h.tool.setShape('area');
+    h.tool.addVertex(-97.75, 30.26);
+    h.tool.addVertex(-97.74, 30.26);
+    h.tool.addVertex(-97.74, 30.27);
+    // src/ui/views/panels/RenderFailure.vue focuses the canvas when the
+    // globe draws again and the control that had focus is gone.
+    h.documentDouble.emit('keydown', {
+      key: 'Enter',
+      target: h.viewer.scene.canvas,
+    });
+    await Promise.resolve();
+    await Promise.resolve();
+    assert.equal(
+      h.annotations.calls.annotate.length,
+      1,
+      'Enter on the canvas finishes',
+    );
     assert.equal(h.annotations.calls.annotate[0].specs[0].type, 'area');
   } finally {
     h.restore();
@@ -422,7 +485,10 @@ test('the live preview hangs at the height the click landed on', async () => {
 
     // …and the finished shape is still flattened, deliberately: the renderer
     // drapes, so a height carried further would be discarded out of sight.
-    h.documentDouble.emit('keydown', { key: 'Enter', target: h.documentDouble.body });
+    h.documentDouble.emit('keydown', {
+      key: 'Enter',
+      target: h.documentDouble.body,
+    });
     await Promise.resolve();
     await Promise.resolve();
     const spec = h.annotations.calls.annotate[0].specs[0];
@@ -478,8 +544,16 @@ test('destroy releases the pointer, the handler, the listeners and the stock act
       stockClick,
       'the viewer got its selecting click back',
     );
-    assert.equal(h.viewer._attached.length, 0, 'the preview data source is detached');
-    assert.equal(h.annotations.listeners.size, 0, 'and it no longer follows the board');
+    assert.equal(
+      h.viewer._attached.length,
+      0,
+      'the preview data source is detached',
+    );
+    assert.equal(
+      h.annotations.listeners.size,
+      0,
+      'and it no longer follows the board',
+    );
 
     // Idempotent: a second destroy is harmless.
     await h.tool.destroy();
@@ -498,7 +572,11 @@ test('Clear wipes the board and the shape in progress', async () => {
 
     h.act('clearDraw');
     assert.equal(h.annotations.calls.clear, 1, 'placed marks are removed');
-    assert.equal(h.tool.session.vertices.length, 0, 'and so is the shape in progress');
+    assert.equal(
+      h.tool.session.vertices.length,
+      0,
+      'and so is the shape in progress',
+    );
   } finally {
     h.restore();
   }
@@ -512,7 +590,13 @@ test('the controls choose the shape and colour the next shape is drawn with; it
     h.act('setDrawColor', 'amber');
     assert.deepEqual(
       { ...h.shown.view, hint: undefined },
-      { active: true, shape: 'line', color: 'amber', hint: undefined, marks: [] },
+      {
+        active: true,
+        shape: 'line',
+        color: 'amber',
+        hint: undefined,
+        marks: [],
+      },
       'the view shows what the controls chose',
     );
     h.act('setDrawColor', 'purple');
@@ -524,7 +608,10 @@ test('the controls choose the shape and colour the next shape is drawn with; it
     assert.equal(h.tool.session.vertices.length, 0);
     h.tool.addVertex(-97.75, 30.26);
     h.tool.addVertex(-97.74, 30.26);
-    h.documentDouble.emit('keydown', { key: 'Enter', target: h.documentDouble.body });
+    h.documentDouble.emit('keydown', {
+      key: 'Enter',
+      target: h.documentDouble.body,
+    });
     await Promise.resolve();
     await Promise.resolve();
     const spec = h.annotations.calls.annotate[0].specs[0];
@@ -549,12 +636,31 @@ test('each drawn shape is a row whose actions reach the board, and fly-to is a n
   try {
     const board = h.annotations;
     board.marks.push(
-      { id: 'a1', type: 'route', manual: true, name: null, label: '950 m', color: 'amber', hidden: false },
-      { id: 'a2', type: 'pin', manual: false, label: 'Voice pin', color: 'primary', hidden: false },
+      {
+        id: 'a1',
+        type: 'route',
+        manual: true,
+        name: null,
+        label: '950 m',
+        color: 'amber',
+        hidden: false,
+      },
+      {
+        id: 'a2',
+        type: 'pin',
+        manual: false,
+        label: 'Voice pin',
+        color: 'primary',
+        hidden: false,
+      },
     );
     board.changed();
     assert.deepEqual(
-      h.shown.view.marks.map(({ id, placeholder, hidden }) => ({ id, placeholder, hidden })),
+      h.shown.view.marks.map(({ id, placeholder, hidden }) => ({
+        id,
+        placeholder,
+        hidden,
+      })),
       [{ id: 'a1', placeholder: 'Line · 950 m', hidden: false }],
       'only hand-drawn marks are listed, an unnamed line by its length',
     );
@@ -569,7 +675,11 @@ test('each drawn shape is a row whose actions reach the board, and fly-to is a n
     ]);
     assert.deepEqual(board.calls.setHidden, [['a1', true]]);
     assert.deepEqual(board.calls.frame, ['a1']);
-    assert.deepEqual(navigations, ['drawing'], 'fly-to goes through the navigation policy');
+    assert.deepEqual(
+      navigations,
+      ['drawing'],
+      'fly-to goes through the navigation policy',
+    );
     assert.deepEqual(board.calls.remove, ['a1']);
     assert.deepEqual(h.shown.view.marks, [], 'the row goes with its mark');
   } finally {
@@ -577,7 +687,7 @@ test('each drawn shape is a row whose actions reach the board, and fly-to is a n
   }
 });
 
-test('an application\'s row actions show on the shapes they are for and run with the shape', async () => {
+test("an application's row actions show on the shapes they are for and run with the shape", async () => {
   const ran = [];
   const h = harness({
     markActions: [
@@ -601,30 +711,102 @@ test('an application\'s row actions show on the shapes they are for and run with
   try {
     const board = h.annotations;
     board.marks.push(
-      { id: 'r1', type: 'area', manual: true, name: 'Strait', color: 'primary', hidden: false, ring: [[29, 41], [29.1, 41], [29.1, 41.1]] },
-      { id: 'l1', type: 'route', manual: true, name: null, label: '9 km', color: 'amber', hidden: false, path: [{ lon: 29, lat: 41.05, height: 0 }, { lon: 29.1, lat: 41.05, height: 0 }] },
-      { id: 'p1', type: 'pin', manual: true, name: 'Camp', color: 'red', hidden: false },
+      {
+        id: 'r1',
+        type: 'area',
+        manual: true,
+        name: 'Strait',
+        color: 'primary',
+        hidden: false,
+        ring: [
+          [29, 41],
+          [29.1, 41],
+          [29.1, 41.1],
+        ],
+      },
+      {
+        id: 'l1',
+        type: 'route',
+        manual: true,
+        name: null,
+        label: '9 km',
+        color: 'amber',
+        hidden: false,
+        path: [
+          { lon: 29, lat: 41.05, height: 0 },
+          { lon: 29.1, lat: 41.05, height: 0 },
+        ],
+      },
+      {
+        id: 'p1',
+        type: 'pin',
+        manual: true,
+        name: 'Camp',
+        color: 'red',
+        hidden: false,
+      },
     );
     board.changed();
     assert.deepEqual(
       h.shown.view.marks.map(({ id, actions }) => [id, actions]),
       [
-        ['r1', [
-          { id: 'tag', icon: 'sell', label: 'Tag Strait' },
-          { id: 'measure', icon: 'straighten', label: 'Measure Strait' },
-        ]],
+        [
+          'r1',
+          [
+            { id: 'tag', icon: 'sell', label: 'Tag Strait' },
+            { id: 'measure', icon: 'straighten', label: 'Measure Strait' },
+          ],
+        ],
         ['l1', [{ id: 'tag', icon: 'sell', label: 'Tag Line · 9 km' }]],
         ['p1', []],
       ],
     );
     assert.equal(h.act('runDrawMarkAction', 'l1', 'tag'), true);
-    assert.equal(h.act('runDrawMarkAction', 'l1', 'measure'), false, 'a line is not offered an area action');
+    assert.equal(
+      h.act('runDrawMarkAction', 'l1', 'measure'),
+      false,
+      'a line is not offered an area action',
+    );
     assert.equal(h.act('runDrawMarkAction', 'p1', 'tag'), false);
     assert.equal(h.act('runDrawMarkAction', 'gone', 'tag'), false);
     assert.equal(h.act('runDrawMarkAction', 'r1', 'measure'), true);
     assert.deepEqual(ran, [
-      ['tag', { id: 'l1', shape: 'line', name: '', title: 'Line · 9 km', geometry: { type: 'LineString', coordinates: [[29, 41.05], [29.1, 41.05]] } }],
-      ['measure', { id: 'r1', shape: 'area', name: 'Strait', title: 'Strait', geometry: { type: 'Polygon', coordinates: [[[29, 41], [29.1, 41], [29.1, 41.1], [29, 41]]] } }],
+      [
+        'tag',
+        {
+          id: 'l1',
+          shape: 'line',
+          name: '',
+          title: 'Line · 9 km',
+          geometry: {
+            type: 'LineString',
+            coordinates: [
+              [29, 41.05],
+              [29.1, 41.05],
+            ],
+          },
+        },
+      ],
+      [
+        'measure',
+        {
+          id: 'r1',
+          shape: 'area',
+          name: 'Strait',
+          title: 'Strait',
+          geometry: {
+            type: 'Polygon',
+            coordinates: [
+              [
+                [29, 41],
+                [29.1, 41],
+                [29.1, 41.1],
+                [29, 41],
+              ],
+            ],
+          },
+        },
+      ],
     ]);
   } finally {
     h.restore();
@@ -634,16 +816,40 @@ test('an application\'s row actions show on the shapes they are for and run with
 test('an action that throws is reported and leaves the row alone', async () => {
   const h = harness({
     markActions: [
-      { id: 'boom', icon: 'bolt', label: () => { throw new Error('label'); }, shapes: ['area'], run: () => { throw new Error('run'); } },
+      {
+        id: 'boom',
+        icon: 'bolt',
+        label: () => {
+          throw new Error('label');
+        },
+        shapes: ['area'],
+        run: () => {
+          throw new Error('run');
+        },
+      },
     ],
   });
   const warn = console.warn;
   const warned = [];
   console.warn = (...args) => warned.push(args[0]);
   try {
-    h.annotations.marks.push({ id: 'r1', type: 'area', manual: true, name: null, color: 'primary', hidden: false, ring: [[0, 0], [1, 0], [1, 1]] });
+    h.annotations.marks.push({
+      id: 'r1',
+      type: 'area',
+      manual: true,
+      name: null,
+      color: 'primary',
+      hidden: false,
+      ring: [
+        [0, 0],
+        [1, 0],
+        [1, 1],
+      ],
+    });
     h.annotations.changed();
-    assert.deepEqual(h.shown.view.marks[0].actions, [{ id: 'boom', icon: 'bolt', label: 'boom' }]);
+    assert.deepEqual(h.shown.view.marks[0].actions, [
+      { id: 'boom', icon: 'bolt', label: 'boom' },
+    ]);
     assert.equal(h.act('runDrawMarkAction', 'r1', 'boom'), false);
     assert.deepEqual(warned, ['[draw] boom failed']);
   } finally {
@@ -652,7 +858,7 @@ test('an action that throws is reported and leaves the row alone', async () => {
   }
 });
 
-test('what a row action answers is its row\'s note; the row is busy until then, and a removed shape drops it', async () => {
+test("what a row action answers is its row's note; the row is busy until then, and a removed shape drops it", async () => {
   const pending = [];
   const h = harness({
     markActions: [
@@ -661,34 +867,73 @@ test('what a row action answers is its row\'s note; the row is busy until then,
         icon: 'straighten',
         label: (name) => `Measure ${name}`,
         shapes: ['area'],
-        run: () => new Promise((resolve, reject) => pending.push({ resolve, reject })),
+        run: () =>
+          new Promise((resolve, reject) => pending.push({ resolve, reject })),
+      },
+      {
+        id: 'now',
+        icon: 'bolt',
+        label: () => 'Now',
+        shapes: ['area'],
+        run: () => '  12 km²  ',
+      },
+      {
+        id: 'long',
+        icon: 'notes',
+        label: () => 'Long',
+        shapes: ['area'],
+        run: () => `${'word '.repeat(60)}end`,
       },
-      { id: 'now', icon: 'bolt', label: () => 'Now', shapes: ['area'], run: () => '  12 km²  ' },
-      { id: 'long', icon: 'notes', label: () => 'Long', shapes: ['area'], run: () => `${'word '.repeat(60)}end` },
     ],
   });
   const warn = console.warn;
   console.warn = () => {};
   try {
     const board = h.annotations;
-    const area = (id) => ({ id, type: 'area', manual: true, name: null, color: 'primary', hidden: false, ring: [[0, 0], [1, 0], [1, 1]] });
+    const area = (id) => ({
+      id,
+      type: 'area',
+      manual: true,
+      name: null,
+      color: 'primary',
+      hidden: false,
+      ring: [
+        [0, 0],
+        [1, 0],
+        [1, 1],
+      ],
+    });
     board.marks.push(area('r1'), area('r2'));
     board.changed();
     const row = (id) => h.shown.view.marks.find((entry) => entry.id === id);
     assert.equal(h.act('runDrawMarkAction', 'r1', 'now'), true);
     assert.deepEqual([row('r1').busy, row('r1').note], [false, '12 km²']);
     h.act('runDrawMarkAction', 'r1', 'long');
-    assert.ok(row('r1').note.length <= 200 && row('r1').note.endsWith('word…'), 'a long note is cut at a word');
+    assert.ok(
+      row('r1').note.length <= 200 && row('r1').note.endsWith('word…'),
+      'a long note is cut at a word',
+    );
     assert.equal(h.act('runDrawMarkAction', 'r1', 'measure'), true);
     assert.deepEqual([row('r1').busy, row('r1').note], [true, '']);
-    assert.equal(h.act('runDrawMarkAction', 'r1', 'now'), false, 'a busy row takes no second press');
+    assert.equal(
+      h.act('runDrawMarkAction', 'r1', 'now'),
+      false,
+      'a busy row takes no second press',
+    );
     pending[0].resolve('412 km², 38 km of edge');
     await new Promise((resolve) => setTimeout(resolve, 0));
-    assert.deepEqual([row('r1').busy, row('r1').note], [false, '412 km², 38 km of edge']);
+    assert.deepEqual(
+      [row('r1').busy, row('r1').note],
+      [false, '412 km², 38 km of edge'],
+    );
     h.act('runDrawMarkAction', 'r1', 'measure');
     pending[1].reject(new Error('refused'));
     await new Promise((resolve) => setTimeout(resolve, 0));
-    assert.deepEqual([row('r1').busy, row('r1').note], [false, ''], 'a failure clears the note');
+    assert.deepEqual(
+      [row('r1').busy, row('r1').note],
+      [false, ''],
+      'a failure clears the note',
+    );
     h.act('runDrawMarkAction', 'r2', 'measure');
     board.marks.splice(1, 1);
     board.changed();
@@ -697,7 +942,11 @@ test('what a row action answers is its row\'s note; the row is busy until then,
     assert.equal(row('r2'), undefined);
     board.marks.push(area('r2'));
     board.changed();
-    assert.deepEqual([row('r2').busy, row('r2').note], [false, ''], 'a late answer never reaches a shape that went');
+    assert.deepEqual(
+      [row('r2').busy, row('r2').note],
+      [false, ''],
+      'a late answer never reaches a shape that went',
+    );
   } finally {
     console.warn = warn;
     h.restore();
@@ -710,30 +959,49 @@ test('Backspace on the page removes the last vertex', () => {
     h.act('toggleDraw');
     h.tool.addVertex(-97.75, 30.26);
     h.tool.addVertex(-97.74, 30.26);
-    h.documentDouble.emit('keydown', { key: 'Backspace', target: h.documentDouble.body });
+    h.documentDouble.emit('keydown', {
+      key: 'Backspace',
+      target: h.documentDouble.body,
+    });
     assert.equal(h.tool.session.vertices.length, 1);
   } finally {
     h.restore();
   }
 });
 
-test('keys on the shape list are the list\'s, not the drawing\'s', async () => {
+test("keys on the shape list are the list's, not the drawing's", async () => {
   const h = harness();
   try {
     const listButton = new FakeElement('BUTTON');
-    listButton.closest = (selector) => (selector === '#draw-mark-list' ? {} : null);
+    listButton.closest = (selector) =>
+      selector === '#draw-mark-list' ? {} : null;
     const elsewhere = new FakeElement('INPUT', 'location-search');
     h.act('toggleDraw');
     h.tool.addVertex(-97.75, 30.26);
     h.tool.addVertex(-97.74, 30.26);
     h.documentDouble.emit('keydown', { key: 'Escape', target: listButton });
-    assert.equal(h.tool.session.vertices.length, 2, 'Escape in the list keeps the shape');
+    assert.equal(
+      h.tool.session.vertices.length,
+      2,
+      'Escape in the list keeps the shape',
+    );
     assert.equal(h.tool.active, true, 'and keeps Draw on');
     h.documentDouble.emit('keydown', { key: 'Enter', target: elsewhere });
     await Promise.resolve();
-    assert.equal(h.annotations.calls.annotate.length, 0, 'another field keeps its Enter');
-    h.documentDouble.emit('keydown', { key: 'Escape', target: h.documentDouble.body });
-    assert.equal(h.tool.session.vertices.length, 0, 'Escape on the page drops the open shape');
+    assert.equal(
+      h.annotations.calls.annotate.length,
+      0,
+      'another field keeps its Enter',
+    );
+    h.documentDouble.emit('keydown', {
+      key: 'Escape',
+      target: h.documentDouble.body,
+    });
+    assert.equal(
+      h.tool.session.vertices.length,
+      0,
+      'Escape on the page drops the open shape',
+    );
   } finally {
     h.restore();
   }

src/ui/renderFailureView.test.mjs

@@ -109,8 +109,17 @@ test('focus goes back where it was when the globe draws again', async (t) => {
   assert.equal(document.activeElement, search);
 });
 
-test('focus goes to the map when the element it came from is gone', async (t) => {
+// The globe's canvas, as CesiumWidget builds it inside the container.
+const addGlobeCanvas = () => {
+  const widget = document.createElement('div');
+  widget.className = 'cesium-widget';
+  document.getElementById('cesiumContainer').appendChild(widget);
+  return widget.appendChild(document.createElement('canvas'));
+};
+
+test('focus goes to the globe canvas when the element it came from is gone', async (t) => {
   const store = mount(t);
+  const canvas = addGlobeCanvas();
   const search = document.body.appendChild(document.createElement('input'));
   search.focus();
   store.publishRenderFailure(failure());
@@ -118,9 +127,29 @@ test('focus goes to the map when the element it came from is gone', async (t) =>
   search.remove();
   store.publishRenderFailure(null);
   await settle();
-  const map = document.getElementById('cesiumContainer');
-  assert.equal(document.activeElement, map);
-  assert.equal(map.getAttribute('tabindex'), '-1');
+  // The map's keys, Enter to finish a drawing among them, read the canvas
+  // as the map (src/annotations/drawTool.js).
+  assert.equal(document.activeElement, canvas);
+  assert.equal(canvas.getAttribute('tabindex'), '-1');
+  canvas.blur();
+  assert.equal(canvas.hasAttribute('tabindex'), false, 'only this once');
+});
+
+test('focus goes to the globe canvas when the element it came from cannot take it', async (t) => {
+  const store = mount(t);
+  const canvas = addGlobeCanvas();
+  const button = document.body.appendChild(document.createElement('button'));
+  button.focus();
+  store.publishRenderFailure(failure());
+  await settle();
+  button.disabled = true;
+  store.publishRenderFailure(null);
+  await settle();
+  assert.equal(document.activeElement, canvas);
+  // A press on the globe leaves focus on the page again, as Cesium has it.
+  canvas.dispatchEvent(new Event('pointerdown'));
+  assert.equal(document.activeElement, document.body);
+  assert.equal(canvas.hasAttribute('tabindex'), false);
 });
 
 test('focus the user moved while the notice was up stays put', async (t) => {

src/ui/views/panels/RenderFailure.vue

@@ -19,8 +19,8 @@ const MESSAGES = {
 };
 // Focus moves to the first action each time the notice appears, so a
 // keyboard user can act on it at once. When the globe draws again, it goes
-// back where it was, or to the map if that is gone, unless the user has moved
-// it since.
+// back where it was, or to the map if that cannot take it, unless the user
+// has moved it since.
 let focusBefore;
 watch(
   () => Boolean(failure.value),
@@ -38,16 +38,43 @@ watch(
     const active = document.activeElement;
     if (active && active !== document.body) return;
     if (previous?.isConnected && previous !== document.body) {
-      previous.focus();
-      return;
+      previous.focus({ preventScroll: true });
+      // A control disabled, hidden or made inert since does not take it.
+      if (document.activeElement === previous) return;
     }
-    const map = document.getElementById('cesiumContainer');
-    if (!map) return;
-    if (!map.hasAttribute('tabindex')) map.tabIndex = -1;
-    map.focus();
+    focusMap();
   },
   { immediate: true },
 );
+
+// The globe's canvas, which the map's keys (Enter to finish a drawing, Space
+// to talk) read as the map. It takes focus only this once: when focus moves
+// on, or the globe is pressed, it goes back to a canvas that cannot take
+// focus, and a press leaves focus on the page, as Cesium has it.
+function focusMap() {
+  const canvas = document.querySelector(
+    '#cesiumContainer .cesium-widget canvas',
+  );
+  if (!canvas) return;
+  if (!canvas.hasAttribute('tabindex')) {
+    canvas.tabIndex = -1;
+    const done = new AbortController();
+    const release = () => {
+      done.abort();
+      canvas.removeAttribute('tabindex');
+    };
+    canvas.addEventListener('blur', release, { signal: done.signal });
+    canvas.addEventListener(
+      'pointerdown',
+      () => {
+        release();
+        canvas.blur();
+      },
+      { capture: true, signal: done.signal },
+    );
+  }
+  canvas.focus({ preventScroll: true });
+}
 </script>
 
 <template>