Editor: Update block editor packages for WordPress 5.8.1.

The following packages were updated:
- @wordpress/a11y to `3.1.2`
- @wordpress/annotations to `2.1.6`
- @wordpress/api-fetch to `5.1.2`
- @wordpress/autop to `3.1.2`
- @wordpress/babel-preset-default to `6.2.1`
- @wordpress/blob to `3.1.2`
- @wordpress/block-directory to `2.1.21`
- @wordpress/block-editor to `6.1.14`
- @wordpress/block-library to `3.2.19`
- @wordpress/block-serialization-default-parser to `4.1.2`
- @wordpress/blocks to `9.1.8`
- @wordpress/components to `14.1.11`
- @wordpress/compose to `4.1.6`
- @wordpress/core-data to `3.1.12`
- @wordpress/customize-widgets to `1.0.20`
- @wordpress/data-controls to `2.1.6`
- @wordpress/data to `5.1.6`
- @wordpress/date to `4.1.2`
- @wordpress/deprecated to `3.1.2`
- @wordpress/dom-ready to `3.1.2`
- @wordpress/dom to `3.1.5`
- @wordpress/e2e-test-utils to `5.3.1`
- @wordpress/edit-post to `4.1.21`
- @wordpress/edit-widgets to `2.1.21`
- @wordpress/editor to `10.1.17`
- @wordpress/element to `3.1.2`
- @wordpress/escape-html to `2.1.2`
- @wordpress/format-library to `2.1.14`
- @wordpress/html-entities to `3.1.2`
- @wordpress/i18n to `4.1.2`
- @wordpress/icons to `4.0.3`
- @wordpress/interface to `3.1.12`
- @wordpress/keyboard-shortcuts to `2.1.7`
- @wordpress/keycodes to `3.1.2`
- @wordpress/list-reusable-blocks to `2.1.11`
- @wordpress/media-utils to `2.1.2`
- @wordpress/notices to `3.1.6`
- @wordpress/nux to `4.1.11`
- @wordpress/plugins to `3.1.6`
- @wordpress/primitives to `2.1.2`
- @wordpress/priority-queue to `2.1.2`
- @wordpress/react-i18n to `2.1.2`
- @wordpress/redux-routine to `4.1.2`
- @wordpress/reusable-blocks to `2.1.17`
- @wordpress/rich-text to `4.1.6`
- @wordpress/scripts to `16.1.5`
- @wordpress/server-side-render to `2.1.12`
- @wordpress/shortcode to `3.1.2`
- @wordpress/url to `3.1.2`
- @wordpress/viewport to `3.1.6`
- @wordpress/warning to `2.1.2`
- @wordpress/widgets to `1.1.19`
- @wordpress/wordcount to `3.1.2`

Props oandregal, juanmaguitar, gziolo, jblz, talldanwp, ribaricplusplus, peterwisoncc, youknowriad, paaljoachim, kreppar, ellatrix, aristath, walbo, ajlende, kevin940726, mamaduka, ntsekouras, toro_unit, mkaz, joen, noisysocks, zieladam, andraganescu, antonvlasenko, terraling, dariak, vladytimy, circlecube, desrosj.
Fixes #54052, #52818.
Built from https://develop.svn.wordpress.org/trunk@51719


git-svn-id: http://core.svn.wordpress.org/trunk@51325 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/css/dist/block-editor/style-rtl.css

@@ -737,7 +737,7 @@
   align-self: center;
   padding: 0;
   list-style: none;
-  margin: 0 0 0 auto;
+  margin: 8px;
 }
 .block-editor-block-list__block .block-list-appender.wp-block {
   max-width: none;

wp-includes/css/dist/block-editor/style.css

@@ -737,7 +737,7 @@
   align-self: center;
   padding: 0;
   list-style: none;
-  margin: 0 auto 0 0;
+  margin: 8px;
 }
 .block-editor-block-list__block .block-list-appender.wp-block {
   max-width: none;

wp-includes/css/dist/edit-widgets/style-rtl.css

@@ -439,6 +439,14 @@ body.is-dragging-components-draggable .wp-block[data-type="core/widget-area"] .c
   pointer-events: none;
 }
 
+.edit-widgets-error-boundary {
+  margin: auto;
+  max-width: 780px;
+  padding: 20px;
+  margin-top: 60px;
+  box-shadow: 0 10px 10px rgba(0, 0, 0, 0.25);
+}
+
 .edit-widgets-header {
   display: flex;
   align-items: center;

wp-includes/css/dist/edit-widgets/style.css

@@ -439,6 +439,14 @@ body.is-dragging-components-draggable .wp-block[data-type="core/widget-area"] .c
   pointer-events: none;
 }
 
+.edit-widgets-error-boundary {
+  margin: auto;
+  max-width: 780px;
+  padding: 20px;
+  margin-top: 60px;
+  box-shadow: 0 10px 10px rgba(0, 0, 0, 0.25);
+}
+
 .edit-widgets-header {
   display: flex;
   align-items: center;

wp-includes/css/dist/widgets/style-rtl.css

@@ -145,6 +145,8 @@
   line-height: 1;
   min-height: 30px;
   padding-right: 8px;
+  padding-top: 8px;
+  padding-bottom: 8px;
 }
 .wp-block-legacy-widget__edit-form .widget-inside.widget-inside select {
   padding-right: 4px;

wp-includes/css/dist/widgets/style.css

@@ -145,6 +145,8 @@
   line-height: 1;
   min-height: 30px;
   padding-left: 8px;
+  padding-top: 8px;
+  padding-bottom: 8px;
 }
 .wp-block-legacy-widget__edit-form .widget-inside.widget-inside select {
   padding-left: 4px;

wp-includes/js/dist/block-editor.js

@@ -17122,6 +17122,26 @@ function DuotoneControl({
 
 /* harmony default export */ var duotone_control = (DuotoneControl);
 
+// CONCATENATED MODULE: ./node_modules/@wordpress/block-editor/build-module/components/block-list/head.js
+
+
+/**
+ * WordPress dependencies
+ */
+
+const head_context = Object(external_wp_element_["createContext"])();
+function Head({
+  children
+}) {
+  const [element, setElement] = Object(external_wp_element_["useState"])();
+  return Object(external_wp_element_["createElement"])(head_context.Provider, {
+    value: element
+  }, Object(external_wp_element_["createElement"])("div", {
+    ref: setElement
+  }), children);
+}
+Head.context = head_context;
+
 // CONCATENATED MODULE: ./node_modules/@wordpress/block-editor/build-module/hooks/duotone.js
 
 
@@ -17139,11 +17159,13 @@ function DuotoneControl({
 
 
 
+
 /**
  * Internal dependencies
  */
 
 
+
 const duotone_EMPTY_ARRAY = [];
 /**
  * Convert a list of colors to an object of R, G, and B values.
@@ -17334,11 +17356,12 @@ const withDuotoneStyles = Object(external_wp_compose_["createHigherOrderComponen
   const selectorsScoped = selectors.map(selector => `.${id} ${selector.trim()}`);
   const selectorsGroup = selectorsScoped.join(', ');
   const className = classnames_default()(props === null || props === void 0 ? void 0 : props.className, id);
-  return Object(external_wp_element_["createElement"])(external_wp_element_["Fragment"], null, Object(external_wp_element_["createElement"])(DuotoneFilter, {
+  const element = Object(external_wp_element_["useContext"])(Head.context);
+  return Object(external_wp_element_["createElement"])(external_wp_element_["Fragment"], null, element && Object(external_wp_element_["createPortal"])(Object(external_wp_element_["createElement"])(DuotoneFilter, {
     selector: selectorsGroup,
     id: id,
     values: getValuesFromColors(values)
-  }), Object(external_wp_element_["createElement"])(BlockListBlock, Object(esm_extends["a" /* default */])({}, props, {
+  }), element), Object(external_wp_element_["createElement"])(BlockListBlock, Object(esm_extends["a" /* default */])({}, props, {
     className: className
   })));
 }, 'withDuotoneStyles');
@@ -17369,6 +17392,7 @@ var build_module_icon = __webpack_require__("iClF");
 
 
 
+
 /**
  * Internal dependencies
  */
@@ -17378,6 +17402,7 @@ var build_module_icon = __webpack_require__("iClF");
 
 
 
+
 function LayoutPanel({
   setAttributes,
   attributes
@@ -17536,10 +17561,11 @@ const withLayoutStyles = Object(external_wp_compose_["createHigherOrderComponent
   } = attributes;
   const usedLayout = !!layout && layout.inherit ? defaultLayout : layout;
   const className = classnames_default()(props === null || props === void 0 ? void 0 : props.className, `wp-container-${id}`);
-  return Object(external_wp_element_["createElement"])(external_wp_element_["Fragment"], null, Object(external_wp_element_["createElement"])(LayoutStyle, {
+  const element = Object(external_wp_element_["useContext"])(Head.context);
+  return Object(external_wp_element_["createElement"])(external_wp_element_["Fragment"], null, element && Object(external_wp_element_["createPortal"])(Object(external_wp_element_["createElement"])(LayoutStyle, {
     selector: `.wp-container-${id}`,
     layout: usedLayout
-  }), Object(external_wp_element_["createElement"])(BlockListBlock, Object(esm_extends["a" /* default */])({}, props, {
+  }), element), Object(external_wp_element_["createElement"])(BlockListBlock, Object(esm_extends["a" /* default */])({}, props, {
     className: className
   })));
 });
@@ -28264,6 +28290,7 @@ function BlockSelectionClearer(props) {
 
 
 
+
 const IntersectionObserver = Object(external_wp_element_["createContext"])();
 
 function Root({
@@ -28290,14 +28317,14 @@ function Root({
       isNavigationMode: _isNavigationMode()
     };
   }, []);
-  return Object(external_wp_element_["createElement"])("div", {
+  return Object(external_wp_element_["createElement"])(Head, null, Object(external_wp_element_["createElement"])("div", {
     ref: Object(external_wp_compose_["useMergeRefs"])([useBlockSelectionClearer(), useBlockDropZone(), useInBetweenInserter()]),
     className: classnames_default()('block-editor-block-list__layout is-root-container', className, {
       'is-outline-mode': isOutlineMode,
       'is-focus-mode': isFocusMode && isLargeViewport,
       'is-navigate-mode': isNavigationMode
     })
-  }, children);
+  }, children));
 }
 
 function BlockList({
@@ -39156,12 +39183,11 @@ function useSelectAll() {
         return;
       }
 
-      const selectedClientIds = getSelectedBlockClientIds();
+      if (!Object(external_wp_dom_["isEntirelySelected"])(event.target)) {
-
-      if (selectedClientIds.length === 1 && !Object(external_wp_dom_["isEntirelySelected"])(event.target)) {
         return;
       }
 
+      const selectedClientIds = getSelectedBlockClientIds();
       const [firstSelectedClientId] = selectedClientIds;
       const rootClientId = getBlockRootClientId(firstSelectedClientId);
       let blockClientIds = getBlockOrder(rootClientId); // If we have selected all sibling nested blocks, try selecting up a

wp-includes/js/dist/block-library.js

@@ -10439,30 +10439,42 @@ function URLPicker({
   setAttributes,
   opensInNewTab,
   onToggleOpenInNewTab,
-  anchorRef
+  anchorRef,
+  richTextRef
 }) {
-  const [isURLPickerOpen, setIsURLPickerOpen] = Object(external_wp_element_["useState"])(false);
+  const [isEditingURL, setIsEditingURL] = Object(external_wp_element_["useState"])(false);
-  const urlIsSet = !!url;
+  const isURLSet = !!url;
-  const urlIsSetandSelected = urlIsSet && isSelected;
 
-  const openLinkControl = () => {
+  const startEditing = event => {
-    setIsURLPickerOpen(true);
+    event.preventDefault();
-    return false; // prevents default behaviour for event
+    setIsEditingURL(true);
   };
 
-  const unlinkButton = () => {
+  const unlink = () => {
     setAttributes({
       url: undefined,
       linkTarget: undefined,
       rel: undefined
     });
-    setIsURLPickerOpen(false);
+    setIsEditingURL(false);
   };
 
-  const linkControl = (isURLPickerOpen || urlIsSetandSelected) && Object(external_wp_element_["createElement"])(external_wp_components_["Popover"], {
+  Object(external_wp_element_["useEffect"])(() => {
+    if (!isSelected) {
+      setIsEditingURL(false);
+    }
+  }, [isSelected]);
+  const isLinkControlVisible = isSelected && (isEditingURL || isURLSet);
+  const linkControl = isLinkControlVisible && Object(external_wp_element_["createElement"])(external_wp_components_["Popover"], {
     position: "bottom center",
-    onClose: () => setIsURLPickerOpen(false),
+    onClose: () => {
-    anchorRef: anchorRef === null || anchorRef === void 0 ? void 0 : anchorRef.current
+      var _richTextRef$current;
+
+      setIsEditingURL(false);
+      (_richTextRef$current = richTextRef.current) === null || _richTextRef$current === void 0 ? void 0 : _richTextRef$current.focus();
+    },
+    anchorRef: anchorRef === null || anchorRef === void 0 ? void 0 : anchorRef.current,
+    focusOnMount: isEditingURL ? 'firstElement' : false
   }, Object(external_wp_element_["createElement"])(external_wp_blockEditor_["__experimentalLinkControl"], {
     className: "wp-block-navigation-link__inline-link-input",
     value: {
@@ -10480,28 +10492,40 @@ function URLPicker({
       if (opensInNewTab !== newOpensInNewTab) {
         onToggleOpenInNewTab(newOpensInNewTab);
       }
-    }
+    },
+    onRemove: () => {
+      var _richTextRef$current2;
+
+      unlink();
+      (_richTextRef$current2 = richTextRef.current) === null || _richTextRef$current2 === void 0 ? void 0 : _richTextRef$current2.focus();
+    },
+    forceIsEditingLink: isEditingURL
   }));
   return Object(external_wp_element_["createElement"])(external_wp_element_["Fragment"], null, Object(external_wp_element_["createElement"])(external_wp_blockEditor_["BlockControls"], {
     group: "block"
-  }, !urlIsSet && Object(external_wp_element_["createElement"])(external_wp_components_["ToolbarButton"], {
+  }, !isURLSet && Object(external_wp_element_["createElement"])(external_wp_components_["ToolbarButton"], {
     name: "link",
     icon: library_link["a" /* default */],
     title: Object(external_wp_i18n_["__"])('Link'),
     shortcut: external_wp_keycodes_["displayShortcut"].primary('k'),
-    onClick: openLinkControl
+    onClick: startEditing
-  }), urlIsSetandSelected && Object(external_wp_element_["createElement"])(external_wp_components_["ToolbarButton"], {
+  }), isURLSet && Object(external_wp_element_["createElement"])(external_wp_components_["ToolbarButton"], {
     name: "link",
     icon: link_off["a" /* default */],
     title: Object(external_wp_i18n_["__"])('Unlink'),
     shortcut: external_wp_keycodes_["displayShortcut"].primaryShift('k'),
-    onClick: unlinkButton,
+    onClick: unlink,
     isActive: true
   })), isSelected && Object(external_wp_element_["createElement"])(external_wp_components_["KeyboardShortcuts"], {
     bindGlobal: true,
     shortcuts: {
-      [external_wp_keycodes_["rawShortcut"].primary('k')]: openLinkControl,
+      [external_wp_keycodes_["rawShortcut"].primary('k')]: startEditing,
-      [external_wp_keycodes_["rawShortcut"].primaryShift('k')]: unlinkButton
+      [external_wp_keycodes_["rawShortcut"].primaryShift('k')]: () => {
+        var _richTextRef$current3;
+
+        unlink();
+        (_richTextRef$current3 = richTextRef.current) === null || _richTextRef$current3 === void 0 ? void 0 : _richTextRef$current3.focus();
+      }
     }
   }), linkControl);
 }
@@ -10557,6 +10581,7 @@ function ButtonEdit(props) {
   const borderRadius = style === null || style === void 0 ? void 0 : (_style$border = style.border) === null || _style$border === void 0 ? void 0 : _style$border.radius;
   const colorProps = Object(external_wp_blockEditor_["__experimentalUseColorProps"])(attributes);
   const ref = Object(external_wp_element_["useRef"])();
+  const richTextRef = Object(external_wp_element_["useRef"])();
   const blockProps = Object(external_wp_blockEditor_["useBlockProps"])({
     ref
   });
@@ -10566,6 +10591,7 @@ function ButtonEdit(props) {
       [`has-custom-font-size`]: blockProps.style.fontSize
     })
   }), Object(external_wp_element_["createElement"])(external_wp_blockEditor_["RichText"], {
+    ref: richTextRef,
     "aria-label": Object(external_wp_i18n_["__"])('Button text'),
     placeholder: placeholder || Object(external_wp_i18n_["__"])('Add text…'),
     value: text,
@@ -10590,7 +10616,8 @@ function ButtonEdit(props) {
     isSelected: isSelected,
     opensInNewTab: linkTarget === '_blank',
     onToggleOpenInNewTab: onToggleOpenInNewTab,
-    anchorRef: ref
+    anchorRef: ref,
+    richTextRef: richTextRef
   }), Object(external_wp_element_["createElement"])(external_wp_blockEditor_["InspectorControls"], null, Object(external_wp_element_["createElement"])(WidthPanel, {
     selectedWidth: width,
     setAttributes: setAttributes

wp-includes/js/dist/core-data.js

@@ -927,11 +927,24 @@ var external_wp_apiFetch_default = /*#__PURE__*/__webpack_require__.n(external_w
 
 // CONCATENATED MODULE: ./node_modules/@wordpress/core-data/build-module/batch/default-processor.js
 /**
- * WordPress dependencies
+ * External dependencies
  */
 
 /**
- * Default batch processor. Sends its input requests to /v1/batch.
+ * WordPress dependencies
+ */
+
+
+/**
+ * Maximum number of requests to place in a single batch request. Obtained by
+ * sending a preflight OPTIONS request to /batch/v1/.
+ *
+ * @type {number?}
+ */
+
+let maxItems = null;
+/**
+ * Default batch processor. Sends its input requests to /batch/v1.
  *
  * @param {Array} requests List of API requests to perform at once.
  *
@@ -941,12 +954,23 @@ var external_wp_apiFetch_default = /*#__PURE__*/__webpack_require__.n(external_w
  */
 
 async function defaultProcessor(requests) {
+  if (maxItems === null) {
+    const preflightResponse = await external_wp_apiFetch_default()({
+      path: '/batch/v1',
+      method: 'OPTIONS'
+    });
+    maxItems = preflightResponse.endpoints[0].args.requests.maxItems;
+  }
+
+  const results = [];
+
+  for (const batchRequests of Object(external_lodash_["chunk"])(requests, maxItems)) {
     const batchResponse = await external_wp_apiFetch_default()({
       path: '/batch/v1',
       method: 'POST',
       data: {
         validation: 'require-all-validate',
-      requests: requests.map(request => ({
+        requests: batchRequests.map(request => ({
           path: request.path,
           body: request.data,
           // Rename 'data' to 'body'.
@@ -955,14 +979,14 @@ async function defaultProcessor(requests) {
         }))
       }
     });
+    let batchResults;
 
     if (batchResponse.failed) {
-    return batchResponse.responses.map(response => ({
+      batchResults = batchResponse.responses.map(response => ({
         error: response === null || response === void 0 ? void 0 : response.body
       }));
-  }
+    } else {
-
+      batchResults = batchResponse.responses.map(response => {
-  return batchResponse.responses.map(response => {
         const result = {};
 
         if (response.status >= 200 && response.status < 300) {
@@ -973,6 +997,12 @@ async function defaultProcessor(requests) {
 
         return result;
       });
+    }
+
+    results.push(...batchResults);
+  }
+
+  return results;
 }
 
 // CONCATENATED MODULE: ./node_modules/@wordpress/core-data/build-module/batch/create-batch.js

wp-includes/js/dist/customize-widgets.js

@@ -122,11 +122,14 @@ __webpack_require__.d(__webpack_exports__, "initialize", function() { return /*
 var selectors_namespaceObject = {};
 __webpack_require__.r(selectors_namespaceObject);
 __webpack_require__.d(selectors_namespaceObject, "__unstableIsFeatureActive", function() { return __unstableIsFeatureActive; });
+__webpack_require__.d(selectors_namespaceObject, "isInserterOpened", function() { return selectors_isInserterOpened; });
+__webpack_require__.d(selectors_namespaceObject, "__experimentalGetInsertionPoint", function() { return __experimentalGetInsertionPoint; });
 
 // NAMESPACE OBJECT: ./node_modules/@wordpress/customize-widgets/build-module/store/actions.js
 var actions_namespaceObject = {};
 __webpack_require__.r(actions_namespaceObject);
 __webpack_require__.d(actions_namespaceObject, "__unstableToggleFeature", function() { return __unstableToggleFeature; });
+__webpack_require__.d(actions_namespaceObject, "setIsInserterOpened", function() { return actions_setIsInserterOpened; });
 
 // EXTERNAL MODULE: external ["wp","element"]
 var external_wp_element_ = __webpack_require__("GRId");
@@ -143,6 +146,72 @@ var external_wp_blocks_ = __webpack_require__("HSyU");
 // EXTERNAL MODULE: external ["wp","components"]
 var external_wp_components_ = __webpack_require__("tI+e");
 
+// EXTERNAL MODULE: external ["wp","i18n"]
+var external_wp_i18n_ = __webpack_require__("l3Sj");
+
+// EXTERNAL MODULE: external ["wp","blockEditor"]
+var external_wp_blockEditor_ = __webpack_require__("axFQ");
+
+// EXTERNAL MODULE: external ["wp","compose"]
+var external_wp_compose_ = __webpack_require__("K9lf");
+
+// CONCATENATED MODULE: ./node_modules/@wordpress/customize-widgets/build-module/components/error-boundary/index.js
+
+
+/**
+ * WordPress dependencies
+ */
+
+
+
+
+
+
+function CopyButton({
+  text,
+  children
+}) {
+  const ref = Object(external_wp_compose_["useCopyToClipboard"])(text);
+  return Object(external_wp_element_["createElement"])(external_wp_components_["Button"], {
+    variant: "secondary",
+    ref: ref
+  }, children);
+}
+
+class error_boundary_ErrorBoundary extends external_wp_element_["Component"] {
+  constructor() {
+    super(...arguments);
+    this.state = {
+      error: null
+    };
+  }
+
+  componentDidCatch(error) {
+    this.setState({
+      error
+    });
+  }
+
+  render() {
+    const {
+      error
+    } = this.state;
+
+    if (!error) {
+      return this.props.children;
+    }
+
+    return Object(external_wp_element_["createElement"])(external_wp_blockEditor_["Warning"], {
+      className: "customize-widgets-error-boundary",
+      actions: [Object(external_wp_element_["createElement"])(CopyButton, {
+        key: "copy-error",
+        text: error.stack
+      }, Object(external_wp_i18n_["__"])('Copy Error'))]
+    }, Object(external_wp_i18n_["__"])('The editor has encountered an unexpected error.'));
+  }
+
+}
+
 // EXTERNAL MODULE: external "lodash"
 var external_lodash_ = __webpack_require__("YLtl");
 
@@ -152,18 +221,12 @@ var external_wp_coreData_ = __webpack_require__("jZUy");
 // EXTERNAL MODULE: external ["wp","data"]
 var external_wp_data_ = __webpack_require__("1ZqX");
 
-// EXTERNAL MODULE: external ["wp","blockEditor"]
-var external_wp_blockEditor_ = __webpack_require__("axFQ");
-
 // EXTERNAL MODULE: external ["wp","mediaUtils"]
 var external_wp_mediaUtils_ = __webpack_require__("6aBm");
 
 // EXTERNAL MODULE: ./node_modules/@babel/runtime/helpers/esm/extends.js
 var esm_extends = __webpack_require__("wx14");
 
-// EXTERNAL MODULE: external ["wp","i18n"]
-var external_wp_i18n_ = __webpack_require__("l3Sj");
-
 // CONCATENATED MODULE: ./node_modules/@wordpress/customize-widgets/build-module/components/block-inspector-button/index.js
 
 
@@ -214,66 +277,9 @@ var library_redo = __webpack_require__("K2cm");
 // EXTERNAL MODULE: ./node_modules/@wordpress/icons/build-module/library/plus.js
 var plus = __webpack_require__("Q4Sy");
 
-// EXTERNAL MODULE: external ["wp","compose"]
-var external_wp_compose_ = __webpack_require__("K9lf");
-
 // EXTERNAL MODULE: ./node_modules/@wordpress/icons/build-module/library/close-small.js
 var close_small = __webpack_require__("bWcr");
 
-// CONCATENATED MODULE: ./node_modules/@wordpress/customize-widgets/build-module/components/inserter/index.js
-
-
-/**
- * WordPress dependencies
- */
-
-
-
-
-
-
-function Inserter({
-  setIsOpened
-}) {
-  const inserterTitleId = Object(external_wp_compose_["useInstanceId"])(Inserter, 'customize-widget-layout__inserter-panel-title');
-  return Object(external_wp_element_["createElement"])("div", {
-    className: "customize-widgets-layout__inserter-panel",
-    "aria-labelledby": inserterTitleId
-  }, Object(external_wp_element_["createElement"])("div", {
-    className: "customize-widgets-layout__inserter-panel-header"
-  }, Object(external_wp_element_["createElement"])("h2", {
-    id: inserterTitleId,
-    className: "customize-widgets-layout__inserter-panel-header-title"
-  }, Object(external_wp_i18n_["__"])('Add a block')), Object(external_wp_element_["createElement"])(external_wp_components_["Button"], {
-    className: "customize-widgets-layout__inserter-panel-header-close-button",
-    icon: close_small["a" /* default */],
-    onClick: () => setIsOpened(false),
-    "aria-label": Object(external_wp_i18n_["__"])('Close inserter')
-  })), Object(external_wp_element_["createElement"])("div", {
-    className: "customize-widgets-layout__inserter-panel-content"
-  }, Object(external_wp_element_["createElement"])(external_wp_blockEditor_["__experimentalLibrary"], {
-    showInserterHelpPanel: true,
-    onSelect: () => setIsOpened(false)
-  })));
-}
-
-/* harmony default export */ var components_inserter = (Inserter);
-
-// EXTERNAL MODULE: ./node_modules/@wordpress/icons/build-module/library/more-vertical.js
-var more_vertical = __webpack_require__("VKE3");
-
-// EXTERNAL MODULE: ./node_modules/@wordpress/icons/build-module/library/external.js
-var external = __webpack_require__("K+tz");
-
-// EXTERNAL MODULE: external ["wp","keyboardShortcuts"]
-var external_wp_keyboardShortcuts_ = __webpack_require__("hF7m");
-
-// EXTERNAL MODULE: ./node_modules/@wordpress/icons/build-module/library/check.js
-var check = __webpack_require__("RMJe");
-
-// EXTERNAL MODULE: external ["wp","a11y"]
-var external_wp_a11y_ = __webpack_require__("gdqT");
-
 // CONCATENATED MODULE: ./node_modules/@wordpress/customize-widgets/build-module/store/defaults.js
 const PREFERENCES_DEFAULTS = {
   features: {
@@ -309,6 +315,22 @@ const PREFERENCES_DEFAULTS = {
 const createWithInitialState = initialState => reducer => {
   return (state = initialState, action) => reducer(state, action);
 };
+/**
+ * Reducer tracking whether the inserter is open.
+ *
+ * @param {boolean|Object} state
+ * @param {Object}         action
+ */
+
+
+function blockInserterPanel(state = false, action) {
+  switch (action.type) {
+    case 'SET_IS_INSERTER_OPENED':
+      return action.value;
+  }
+
+  return state;
+}
 /**
  * Reducer returning the user preferences.
  *
@@ -332,6 +354,7 @@ const preferences = Object(external_lodash_["flow"])([external_wp_data_["combine
 
 });
 /* harmony default export */ var reducer = (Object(external_wp_data_["combineReducers"])({
+  blockInserterPanel,
   preferences
 }));
 
@@ -356,6 +379,35 @@ const preferences = Object(external_lodash_["flow"])([external_wp_data_["combine
 function __unstableIsFeatureActive(state, feature) {
   return Object(external_lodash_["get"])(state.preferences.features, [feature], false);
 }
+/**
+ * Returns true if the inserter is opened.
+ *
+ * @param {Object} state Global application state.
+ *
+ * @return {boolean} Whether the inserter is opened.
+ */
+
+function selectors_isInserterOpened(state) {
+  return !!state.blockInserterPanel;
+}
+/**
+ * Get the insertion point for the inserter.
+ *
+ * @param {Object} state Global application state.
+ *
+ * @return {Object} The root client ID and index to insert at.
+ */
+
+function __experimentalGetInsertionPoint(state) {
+  const {
+    rootClientId,
+    insertionIndex
+  } = state.blockInserterPanel;
+  return {
+    rootClientId,
+    insertionIndex
+  };
+}
 
 // CONCATENATED MODULE: ./node_modules/@wordpress/customize-widgets/build-module/store/actions.js
 /**
@@ -375,6 +427,25 @@ function __unstableToggleFeature(feature) {
     feature
   };
 }
+/**
+ * Returns an action object used to open/close the inserter.
+ *
+ * @param {boolean|Object} value                Whether the inserter should be
+ *                                              opened (true) or closed (false).
+ *                                              To specify an insertion point,
+ *                                              use an object.
+ * @param {string}         value.rootClientId   The root client ID to insert at.
+ * @param {number}         value.insertionIndex The index to insert at.
+ *
+ * @return {Object} Action object.
+ */
+
+function actions_setIsInserterOpened(value) {
+  return {
+    type: 'SET_IS_INSERTER_OPENED',
+    value
+  };
+}
 
 // CONCATENATED MODULE: ./node_modules/@wordpress/customize-widgets/build-module/store/constants.js
 /**
@@ -422,6 +493,69 @@ const store = Object(external_wp_data_["createReduxStore"])(STORE_NAME, storeCon
 
 Object(external_wp_data_["registerStore"])(STORE_NAME, storeConfig);
 
+// CONCATENATED MODULE: ./node_modules/@wordpress/customize-widgets/build-module/components/inserter/index.js
+
+
+/**
+ * WordPress dependencies
+ */
+
+
+
+
+
+
+/**
+ * Internal dependencies
+ */
+
+
+
+function Inserter({
+  setIsOpened
+}) {
+  const inserterTitleId = Object(external_wp_compose_["useInstanceId"])(Inserter, 'customize-widget-layout__inserter-panel-title');
+  const insertionPoint = Object(external_wp_data_["useSelect"])(select => select(store).__experimentalGetInsertionPoint());
+  return Object(external_wp_element_["createElement"])("div", {
+    className: "customize-widgets-layout__inserter-panel",
+    "aria-labelledby": inserterTitleId
+  }, Object(external_wp_element_["createElement"])("div", {
+    className: "customize-widgets-layout__inserter-panel-header"
+  }, Object(external_wp_element_["createElement"])("h2", {
+    id: inserterTitleId,
+    className: "customize-widgets-layout__inserter-panel-header-title"
+  }, Object(external_wp_i18n_["__"])('Add a block')), Object(external_wp_element_["createElement"])(external_wp_components_["Button"], {
+    className: "customize-widgets-layout__inserter-panel-header-close-button",
+    icon: close_small["a" /* default */],
+    onClick: () => setIsOpened(false),
+    "aria-label": Object(external_wp_i18n_["__"])('Close inserter')
+  })), Object(external_wp_element_["createElement"])("div", {
+    className: "customize-widgets-layout__inserter-panel-content"
+  }, Object(external_wp_element_["createElement"])(external_wp_blockEditor_["__experimentalLibrary"], {
+    rootClientId: insertionPoint.rootClientId,
+    __experimentalInsertionIndex: insertionPoint.insertionIndex,
+    showInserterHelpPanel: true,
+    onSelect: () => setIsOpened(false)
+  })));
+}
+
+/* harmony default export */ var components_inserter = (Inserter);
+
+// EXTERNAL MODULE: ./node_modules/@wordpress/icons/build-module/library/more-vertical.js
+var more_vertical = __webpack_require__("VKE3");
+
+// EXTERNAL MODULE: ./node_modules/@wordpress/icons/build-module/library/external.js
+var external = __webpack_require__("K+tz");
+
+// EXTERNAL MODULE: external ["wp","keyboardShortcuts"]
+var external_wp_keyboardShortcuts_ = __webpack_require__("hF7m");
+
+// EXTERNAL MODULE: ./node_modules/@wordpress/icons/build-module/library/check.js
+var check = __webpack_require__("RMJe");
+
+// EXTERNAL MODULE: external ["wp","a11y"]
+var external_wp_a11y_ = __webpack_require__("gdqT");
+
 // CONCATENATED MODULE: ./node_modules/@wordpress/customize-widgets/build-module/components/more-menu/feature-toggle.js
 
 
@@ -804,7 +938,7 @@ function MoreMenu() {
   }), Object(external_wp_element_["createElement"])(external_wp_components_["MenuItem"], {
     role: "menuitem",
     icon: external["a" /* default */],
-    href: Object(external_wp_i18n_["__"])('https://wordpress.org/support/article/wordpress-editor/'),
+    href: Object(external_wp_i18n_["__"])('https://wordpress.org/support/article/block-based-widgets-editor/'),
     target: "_blank",
     rel: "noopener noreferrer"
   }, Object(external_wp_i18n_["__"])('Help'), Object(external_wp_element_["createElement"])(external_wp_components_["VisuallyHidden"], {
@@ -914,24 +1048,33 @@ function Header({
  * WordPress dependencies
  */
 
+
+/**
+ * Internal dependencies
+ */
+
+
 function useInserter(inserter) {
-  const [isInserterOpened, setIsInserterOpened] = Object(external_wp_element_["useState"])(() => inserter.isOpen);
+  const isInserterOpened = Object(external_wp_data_["useSelect"])(select => select(store).isInserterOpened());
+  const {
+    setIsInserterOpened
+  } = Object(external_wp_data_["useDispatch"])(store);
   Object(external_wp_element_["useEffect"])(() => {
-    return inserter.subscribe(setIsInserterOpened);
+    if (isInserterOpened) {
-  }, [inserter]);
-  return [isInserterOpened, Object(external_wp_element_["useCallback"])(updater => {
-    let isOpen = updater;
-
-    if (typeof updater === 'function') {
-      isOpen = updater(inserter.isOpen);
-    }
-
-    if (isOpen) {
       inserter.open();
     } else {
       inserter.close();
     }
-  }, [inserter])];
+  }, [inserter, isInserterOpened]);
+  return [isInserterOpened, Object(external_wp_element_["useCallback"])(updater => {
+    let isOpen = updater;
+
+    if (typeof updater === 'function') {
+      isOpen = updater(Object(external_wp_data_["select"])(store).isInserterOpened());
+    }
+
+    setIsInserterOpened(isOpen);
+  }, [setIsInserterOpened])];
 }
 
 // EXTERNAL MODULE: external ["wp","isShallowEqual"]
@@ -1542,7 +1685,7 @@ function SidebarBlockEditor({
       keepCaretInsideBlock,
       __unstableHasCustomAppender: true
     };
-  }, [hasUploadPermissions, blockEditorSettings, isFixedToolbarActive, keepCaretInsideBlock]);
+  }, [hasUploadPermissions, blockEditorSettings, isFixedToolbarActive, keepCaretInsideBlock, setIsInserterOpened]);
 
   if (isWelcomeGuideActive) {
     return Object(external_wp_element_["createElement"])(WelcomeGuide, {
@@ -1696,6 +1839,7 @@ function useClearSelectedBlock(sidebarControl, popoverRef) {
 
 
 
+
 function CustomizeWidgets({
   api,
   sidebarControls,
@@ -1715,13 +1859,13 @@ function CustomizeWidgets({
       unsubscribers.forEach(unsubscriber => unsubscriber());
     };
   }, [sidebarControls]);
-  const activeSidebar = activeSidebarControl && Object(external_wp_element_["createPortal"])(Object(external_wp_element_["createElement"])(SidebarBlockEditor, {
+  const activeSidebar = activeSidebarControl && Object(external_wp_element_["createPortal"])(Object(external_wp_element_["createElement"])(error_boundary_ErrorBoundary, null, Object(external_wp_element_["createElement"])(SidebarBlockEditor, {
     key: activeSidebarControl.id,
     blockEditorSettings: blockEditorSettings,
     sidebar: activeSidebarControl.sidebarAdapter,
     inserter: activeSidebarControl.inserter,
     inspector: activeSidebarControl.inspector
-  }), activeSidebarControl.container[0]); // We have to portal this to the parent of both the editor and the inspector,
+  })), activeSidebarControl.container[0]); // We have to portal this to the parent of both the editor and the inspector,
   // so that the popovers will appear above both of them.
 
   const popover = parentContainer && Object(external_wp_element_["createPortal"])(Object(external_wp_element_["createElement"])("div", {
@@ -1838,7 +1982,9 @@ function getSidebarSection() {
           var _args$completeCallbac;
 
           controls.forEach(control => {
-            control.onChangeSectionExpanded(expanded, args);
+            var _control$onChangeSect;
+
+            (_control$onChangeSect = control.onChangeSectionExpanded) === null || _control$onChangeSect === void 0 ? void 0 : _control$onChangeSect.call(control, expanded, args);
           });
           (_args$completeCallbac = _args.completeCallback) === null || _args$completeCallbac === void 0 ? void 0 : _args$completeCallbac.call(_args);
         }
@@ -2204,6 +2350,12 @@ var external_wp_dom_ = __webpack_require__("1CF3");
  */
 
 
+
+/**
+ * Internal dependencies
+ */
+
+
 function getInserterOuterSection() {
   const {
     wp: {
@@ -2242,28 +2394,31 @@ function getInserterOuterSection() {
       const ownerWindow = this.contentContainer[0].ownerDocument.defaultView; // Handle closing the inserter when pressing the Escape key.
 
       ownerWindow.addEventListener('keydown', event => {
-        if (this.isOpen && (event.keyCode === external_wp_keycodes_["ESCAPE"] || event.code === 'Escape')) {
+        if (this.expanded() && (event.keyCode === external_wp_keycodes_["ESCAPE"] || event.code === 'Escape')) {
           event.stopPropagation();
-          this.close();
+          Object(external_wp_data_["dispatch"])(store).setIsInserterOpened(false);
         }
       }, // Use capture mode to make this run before other event listeners.
       true);
-      this.contentContainer.addClass('widgets-inserter');
+      this.contentContainer.addClass('widgets-inserter'); // Set a flag if the state is being changed from open() or close().
+      // Don't propagate the event if it's an internal action to prevent infinite loop.
+
+      this.isFromInternalAction = false;
+      this.expanded.bind(() => {
+        if (!this.isFromInternalAction) {
+          // Propagate the event to React to sync the state.
+          Object(external_wp_data_["dispatch"])(store).setIsInserterOpened(this.expanded());
         }
 
-    get isOpen() {
+        this.isFromInternalAction = false;
-      return this.expanded();
+      });
-    }
-
-    subscribe(handler) {
-      this.expanded.bind(handler);
-      return () => this.expanded.unbind(handler);
     }
 
     open() {
-      if (!this.isOpen) {
+      if (!this.expanded()) {
         const contentContainer = this.contentContainer[0];
         this.activeElementBeforeExpanded = contentContainer.ownerDocument.activeElement;
+        this.isFromInternalAction = true;
         this.expand({
           completeCallback() {
             // We have to do this in a "completeCallback" or else the elements will not yet be visible/tabbable.
@@ -2281,9 +2436,10 @@ function getInserterOuterSection() {
     }
 
     close() {
-      if (this.isOpen) {
+      if (this.expanded()) {
         const contentContainer = this.contentContainer[0];
         const activeElement = contentContainer.ownerDocument.activeElement;
+        this.isFromInternalAction = true;
         this.collapse({
           completeCallback() {
             // Return back the focus when closing the inserter.
@@ -2307,12 +2463,18 @@ function getInserterOuterSection() {
 }
 
 // CONCATENATED MODULE: ./node_modules/@wordpress/customize-widgets/build-module/controls/sidebar-control.js
+/**
+ * WordPress dependencies
+ */
+
 /**
  * Internal dependencies
  */
 
 
 
+
+
 const getInserterId = controlId => `widgets-inserter-${controlId}`;
 
 function getSidebarControl() {
@@ -2347,7 +2509,7 @@ function getSidebarControl() {
       if (!args.unchanged) {
         // Close the inserter when the section collapses.
         if (!expanded) {
-          this.inserter.close();
+          Object(external_wp_data_["dispatch"])(store).setIsInserterOpened(false);
         }
 
         this.subscribers.forEach(subscriber => subscriber(expanded, args));

wp-includes/js/dist/data.js

@@ -755,6 +755,55 @@ function isPlainObject(obj) {
   return Object.getPrototypeOf(obj) === proto;
 }
 
+// Inlined / shortened version of `kindOf` from https://github.com/jonschlinkert/kind-of
+function miniKindOf(val) {
+  if (val === void 0) return 'undefined';
+  if (val === null) return 'null';
+  var type = typeof val;
+
+  switch (type) {
+    case 'boolean':
+    case 'string':
+    case 'number':
+    case 'symbol':
+    case 'function':
+      {
+        return type;
+      }
+  }
+
+  if (Array.isArray(val)) return 'array';
+  if (isDate(val)) return 'date';
+  if (isError(val)) return 'error';
+  var constructorName = ctorName(val);
+
+  switch (constructorName) {
+    case 'Symbol':
+    case 'Promise':
+    case 'WeakMap':
+    case 'WeakSet':
+    case 'Map':
+    case 'Set':
+      return constructorName;
+  } // other
+
+
+  return type.slice(8, -1).toLowerCase().replace(/\s/g, '');
+}
+
+function ctorName(val) {
+  return typeof val.constructor === 'function' ? val.constructor.name : null;
+}
+
+function isError(val) {
+  return val instanceof Error || typeof val.message === 'string' && val.constructor && typeof val.constructor.stackTraceLimit === 'number';
+}
+
+function isDate(val) {
+  if (val instanceof Date) return true;
+  return typeof val.toDateString === 'function' && typeof val.getDate === 'function' && typeof val.setDate === 'function';
+}
+
 function kindOf(val) {
   var typeOfVal = typeof val;
 

wp-includes/js/dist/edit-post.js

@@ -634,6 +634,7 @@ __webpack_require__.d(actions_namespaceObject, "setIsInserterOpened", function()
 __webpack_require__.d(actions_namespaceObject, "setIsListViewOpened", function() { return setIsListViewOpened; });
 __webpack_require__.d(actions_namespaceObject, "setIsEditingTemplate", function() { return setIsEditingTemplate; });
 __webpack_require__.d(actions_namespaceObject, "__unstableSwitchToTemplateMode", function() { return __unstableSwitchToTemplateMode; });
+__webpack_require__.d(actions_namespaceObject, "initializeMetaBoxes", function() { return initializeMetaBoxes; });
 
 // NAMESPACE OBJECT: ./node_modules/@wordpress/edit-post/build-module/store/selectors.js
 var selectors_namespaceObject = {};
@@ -656,13 +657,14 @@ __webpack_require__.d(selectors_namespaceObject, "isMetaBoxLocationVisible", fun
 __webpack_require__.d(selectors_namespaceObject, "isMetaBoxLocationActive", function() { return isMetaBoxLocationActive; });
 __webpack_require__.d(selectors_namespaceObject, "getMetaBoxesPerLocation", function() { return getMetaBoxesPerLocation; });
 __webpack_require__.d(selectors_namespaceObject, "getAllMetaBoxes", function() { return getAllMetaBoxes; });
-__webpack_require__.d(selectors_namespaceObject, "hasMetaBoxes", function() { return hasMetaBoxes; });
+__webpack_require__.d(selectors_namespaceObject, "hasMetaBoxes", function() { return selectors_hasMetaBoxes; });
 __webpack_require__.d(selectors_namespaceObject, "isSavingMetaBoxes", function() { return selectors_isSavingMetaBoxes; });
 __webpack_require__.d(selectors_namespaceObject, "__experimentalGetPreviewDeviceType", function() { return __experimentalGetPreviewDeviceType; });
 __webpack_require__.d(selectors_namespaceObject, "isInserterOpened", function() { return isInserterOpened; });
 __webpack_require__.d(selectors_namespaceObject, "__experimentalGetInsertionPoint", function() { return __experimentalGetInsertionPoint; });
 __webpack_require__.d(selectors_namespaceObject, "isListViewOpened", function() { return isListViewOpened; });
 __webpack_require__.d(selectors_namespaceObject, "isEditingTemplate", function() { return selectors_isEditingTemplate; });
+__webpack_require__.d(selectors_namespaceObject, "areMetaBoxesInitialized", function() { return areMetaBoxesInitialized; });
 __webpack_require__.d(selectors_namespaceObject, "getEditedPostTemplate", function() { return getEditedPostTemplate; });
 
 // EXTERNAL MODULE: external ["wp","data"]
@@ -1005,10 +1007,29 @@ function isEditingTemplate(state = false, action) {
 
   return state;
 }
+/**
+ * Reducer tracking whether meta boxes are initialized.
+ *
+ * @param {boolean} state
+ * @param {Object}  action
+ *
+ * @return {boolean} Updated state.
+ */
+
+
+function metaBoxesInitialized(state = false, action) {
+  switch (action.type) {
+    case 'META_BOXES_INITIALIZED':
+      return true;
+  }
+
+  return state;
+}
 
 const metaBoxes = Object(external_wp_data_["combineReducers"])({
   isSaving: isSavingMetaBoxes,
-  locations: metaBoxLocations
+  locations: metaBoxLocations,
+  initialized: metaBoxesInitialized
 });
 /* harmony default export */ var reducer = (Object(external_wp_data_["combineReducers"])({
   activeModal,
@@ -1301,7 +1322,6 @@ function showBlockTypes(blockNames) {
     blockNames: Object(external_lodash_["castArray"])(blockNames)
   };
 }
-let saveMetaboxUnsubscribe;
 /**
  * Returns an action object used in signaling
  * what Meta boxes are available in which location.
@@ -1316,38 +1336,6 @@ function* setAvailableMetaBoxesPerLocation(metaBoxesPerLocation) {
     type: 'SET_META_BOXES_PER_LOCATIONS',
     metaBoxesPerLocation
   };
-  const postType = yield external_wp_data_["controls"].select('core/editor', 'getCurrentPostType');
-
-  if (window.postboxes.page !== postType) {
-    window.postboxes.add_postbox_toggles(postType);
-  }
-
-  let wasSavingPost = yield external_wp_data_["controls"].select('core/editor', 'isSavingPost');
-  let wasAutosavingPost = yield external_wp_data_["controls"].select('core/editor', 'isAutosavingPost'); // Meta boxes are initialized once at page load. It is not necessary to
-  // account for updates on each state change.
-  //
-  // See: https://github.com/WordPress/WordPress/blob/5.1.1/wp-admin/includes/post.php#L2307-L2309
-
-  const hasActiveMetaBoxes = yield external_wp_data_["controls"].select(store.name, 'hasMetaBoxes'); // First remove any existing subscription in order to prevent multiple saves
-
-  if (!!saveMetaboxUnsubscribe) {
-    saveMetaboxUnsubscribe();
-  } // Save metaboxes when performing a full save on the post.
-
-
-  saveMetaboxUnsubscribe = Object(external_wp_data_["subscribe"])(() => {
-    const isSavingPost = Object(external_wp_data_["select"])('core/editor').isSavingPost();
-    const isAutosavingPost = Object(external_wp_data_["select"])('core/editor').isAutosavingPost(); // Save metaboxes on save completion, except for autosaves that are not a post preview.
-
-    const shouldTriggerMetaboxesSave = hasActiveMetaBoxes && wasSavingPost && !isSavingPost && !wasAutosavingPost; // Save current state for next inspection.
-
-    wasSavingPost = isSavingPost;
-    wasAutosavingPost = isAutosavingPost;
-
-    if (shouldTriggerMetaboxesSave) {
-      Object(external_wp_data_["dispatch"])(store.name).requestMetaBoxUpdates();
-    }
-  });
 }
 /**
  * Returns an action object used to request meta box update.
@@ -1485,6 +1473,55 @@ function* __unstableSwitchToTemplateMode(template) {
     });
   }
 }
+let actions_metaBoxesInitialized = false;
+/**
+ * Initializes WordPress `postboxes` script and the logic for saving meta boxes.
+ */
+
+function* initializeMetaBoxes() {
+  const isEditorReady = yield external_wp_data_["controls"].select('core/editor', '__unstableIsEditorReady');
+
+  if (!isEditorReady) {
+    return;
+  }
+
+  const postType = yield external_wp_data_["controls"].select('core/editor', 'getCurrentPostType'); // Only initialize once.
+
+  if (actions_metaBoxesInitialized) {
+    return;
+  }
+
+  if (window.postboxes.page !== postType) {
+    window.postboxes.add_postbox_toggles(postType);
+  }
+
+  actions_metaBoxesInitialized = true;
+  let wasSavingPost = yield external_wp_data_["controls"].select('core/editor', 'isSavingPost');
+  let wasAutosavingPost = yield external_wp_data_["controls"].select('core/editor', 'isAutosavingPost');
+  const hasMetaBoxes = yield external_wp_data_["controls"].select(store, 'hasMetaBoxes'); // Save metaboxes when performing a full save on the post.
+
+  Object(external_wp_data_["subscribe"])(() => {
+    const isSavingPost = Object(external_wp_data_["select"])('core/editor').isSavingPost();
+    const isAutosavingPost = Object(external_wp_data_["select"])('core/editor').isAutosavingPost(); // Save metaboxes on save completion, except for autosaves that are not a post preview.
+    //
+    // Meta boxes are initialized once at page load. It is not necessary to
+    // account for updates on each state change.
+    //
+    // See: https://github.com/WordPress/WordPress/blob/5.1.1/wp-admin/includes/post.php#L2307-L2309
+
+    const shouldTriggerMetaboxesSave = hasMetaBoxes && wasSavingPost && !isSavingPost && !wasAutosavingPost; // Save current state for next inspection.
+
+    wasSavingPost = isSavingPost;
+    wasAutosavingPost = isAutosavingPost;
+
+    if (shouldTriggerMetaboxesSave) {
+      Object(external_wp_data_["dispatch"])(store).requestMetaBoxUpdates();
+    }
+  });
+  return {
+    type: 'META_BOXES_INITIALIZED'
+  };
+}
 
 // EXTERNAL MODULE: ./node_modules/rememo/es/rememo.js
 var rememo = __webpack_require__("pPDe");
@@ -1744,7 +1781,7 @@ const getAllMetaBoxes = Object(rememo["a" /* default */])(state => {
  * @return {boolean} Whether there are metaboxes or not.
  */
 
-function hasMetaBoxes(state) {
+function selectors_hasMetaBoxes(state) {
   return getActiveMetaBoxLocations(state).length > 0;
 }
 /**
@@ -1820,6 +1857,17 @@ function isListViewOpened(state) {
 function selectors_isEditingTemplate(state) {
   return state.isEditingTemplate;
 }
+/**
+ * Returns true if meta boxes are initialized.
+ *
+ * @param {Object} state Global application state.
+ *
+ * @return {boolean} Whether meta boxes are initialized.
+ */
+
+function areMetaBoxesInitialized(state) {
+  return state.metaBoxes.initialized;
+}
 /**
  * Retrieves the template of the currently edited post.
  *
@@ -3348,7 +3396,6 @@ const arrowLeft = Object(_wordpress_element__WEBPACK_IMPORTED_MODULE_0__["create
 __webpack_require__.r(__webpack_exports__);
 
 // EXPORTS
-__webpack_require__.d(__webpack_exports__, "store", function() { return /* reexport */ store["a" /* store */]; });
 __webpack_require__.d(__webpack_exports__, "reinitializeEditor", function() { return /* binding */ reinitializeEditor; });
 __webpack_require__.d(__webpack_exports__, "initializeEditor", function() { return /* binding */ initializeEditor; });
 __webpack_require__.d(__webpack_exports__, "PluginBlockSettingsMenuItem", function() { return /* reexport */ plugin_block_settings_menu_item; });
@@ -3361,6 +3408,7 @@ __webpack_require__.d(__webpack_exports__, "PluginSidebar", function() { return
 __webpack_require__.d(__webpack_exports__, "PluginSidebarMoreMenuItem", function() { return /* reexport */ PluginSidebarMoreMenuItem; });
 __webpack_require__.d(__webpack_exports__, "__experimentalFullscreenModeClose", function() { return /* reexport */ fullscreen_mode_close; });
 __webpack_require__.d(__webpack_exports__, "__experimentalMainDashboardButton", function() { return /* reexport */ main_dashboard_button; });
+__webpack_require__.d(__webpack_exports__, "store", function() { return /* reexport */ store["a" /* store */]; });
 
 // EXTERNAL MODULE: external ["wp","element"]
 var external_wp_element_ = __webpack_require__("GRId");
@@ -4000,7 +4048,7 @@ function __spreadArray(to, from, pack) {
             ar[i] = from[i];
         }
     }
-    return to.concat(ar || from);
+    return to.concat(ar || Array.prototype.slice.call(from));
 }
 
 function __await(v) {
@@ -5053,7 +5101,7 @@ function tslib_es6_spreadArray(to, from, pack) {
             ar[i] = from[i];
         }
     }
-    return to.concat(ar || from);
+    return to.concat(ar || Array.prototype.slice.call(from));
 }
 
 function tslib_es6_await(v) {
@@ -6601,7 +6649,7 @@ function tslib_tslib_es6_spreadArray(to, from, pack) {
             ar[i] = from[i];
         }
     }
-    return to.concat(ar || from);
+    return to.concat(ar || Array.prototype.slice.call(from));
 }
 
 function tslib_tslib_es6_await(v) {
@@ -16626,6 +16674,8 @@ class meta_box_visibility_MetaBoxVisibility extends external_wp_element_["Compon
  */
 
 
+
+
 /**
  * Internal dependencies
  */
@@ -16633,12 +16683,44 @@ class meta_box_visibility_MetaBoxVisibility extends external_wp_element_["Compon
 
 
 
-
 function MetaBoxes({
-  location,
+  location
-  isVisible,
-  metaBoxes
 }) {
+  const registry = Object(external_wp_data_["useRegistry"])();
+  const {
+    metaBoxes,
+    isVisible,
+    areMetaBoxesInitialized,
+    isEditorReady
+  } = Object(external_wp_data_["useSelect"])(select => {
+    const {
+      __unstableIsEditorReady
+    } = select(external_wp_editor_["store"]);
+    const {
+      isMetaBoxLocationVisible,
+      getMetaBoxesPerLocation,
+      areMetaBoxesInitialized: _areMetaBoxesInitialized
+    } = select(store["a" /* store */]);
+    return {
+      metaBoxes: getMetaBoxesPerLocation(location),
+      isVisible: isMetaBoxLocationVisible(location),
+      areMetaBoxesInitialized: _areMetaBoxesInitialized(),
+      isEditorReady: __unstableIsEditorReady()
+    };
+  }, [location]); // When editor is ready, initialize postboxes (wp core script) and metabox
+  // saving. This initializes all meta box locations, not just this specific
+  // one.
+
+  Object(external_wp_element_["useEffect"])(() => {
+    if (isEditorReady && !areMetaBoxesInitialized) {
+      registry.dispatch(store["a" /* store */]).initializeMetaBoxes();
+    }
+  }, [isEditorReady, areMetaBoxesInitialized]);
+
+  if (!areMetaBoxesInitialized) {
+    return null;
+  }
+
   return Object(external_wp_element_["createElement"])(external_wp_element_["Fragment"], null, Object(external_lodash_["map"])(metaBoxes, ({
     id
   }) => Object(external_wp_element_["createElement"])(meta_box_visibility, {
@@ -16649,19 +16731,6 @@ function MetaBoxes({
   }));
 }
 
-/* harmony default export */ var meta_boxes = (Object(external_wp_data_["withSelect"])((select, {
-  location
-}) => {
-  const {
-    isMetaBoxLocationVisible,
-    getMetaBoxesPerLocation
-  } = select(store["a" /* store */]);
-  return {
-    metaBoxes: getMetaBoxesPerLocation(location),
-    isVisible: isMetaBoxLocationVisible(location)
-  };
-})(MetaBoxes));
-
 // EXTERNAL MODULE: ./node_modules/@wordpress/edit-post/build-module/components/sidebar/plugin-document-setting-panel/index.js
 var plugin_document_setting_panel = __webpack_require__("xrib");
 
@@ -17158,7 +17227,7 @@ const SettingsSidebar = () => {
     toggleShortcut: keyboardShortcut,
     icon: cog["a" /* default */],
     isActiveByDefault: SIDEBAR_ACTIVE_BY_DEFAULT
-  }, !isTemplateMode && sidebarName === 'edit-post/document' && Object(external_wp_element_["createElement"])(external_wp_element_["Fragment"], null, Object(external_wp_element_["createElement"])(post_status, null), Object(external_wp_element_["createElement"])(sidebar_template, null), Object(external_wp_element_["createElement"])(plugin_document_setting_panel["a" /* default */].Slot, null), Object(external_wp_element_["createElement"])(last_revision, null), Object(external_wp_element_["createElement"])(post_link, null), Object(external_wp_element_["createElement"])(post_taxonomies, null), Object(external_wp_element_["createElement"])(featured_image, null), Object(external_wp_element_["createElement"])(post_excerpt, null), Object(external_wp_element_["createElement"])(discussion_panel, null), Object(external_wp_element_["createElement"])(page_attributes, null), Object(external_wp_element_["createElement"])(meta_boxes, {
+  }, !isTemplateMode && sidebarName === 'edit-post/document' && Object(external_wp_element_["createElement"])(external_wp_element_["Fragment"], null, Object(external_wp_element_["createElement"])(post_status, null), Object(external_wp_element_["createElement"])(sidebar_template, null), Object(external_wp_element_["createElement"])(plugin_document_setting_panel["a" /* default */].Slot, null), Object(external_wp_element_["createElement"])(last_revision, null), Object(external_wp_element_["createElement"])(post_link, null), Object(external_wp_element_["createElement"])(post_taxonomies, null), Object(external_wp_element_["createElement"])(featured_image, null), Object(external_wp_element_["createElement"])(post_excerpt, null), Object(external_wp_element_["createElement"])(discussion_panel, null), Object(external_wp_element_["createElement"])(page_attributes, null), Object(external_wp_element_["createElement"])(MetaBoxes, {
     location: "side"
   })), isTemplateMode && sidebarName === 'edit-post/document' && Object(external_wp_element_["createElement"])(template_summary, null), sidebarName === 'edit-post/block' && Object(external_wp_element_["createElement"])(external_wp_blockEditor_["BlockInspector"], null));
 };
@@ -17769,9 +17838,9 @@ function Layout({
       styles: styles
     }), !isTemplateMode && Object(external_wp_element_["createElement"])("div", {
       className: "edit-post-layout__metaboxes"
-    }, Object(external_wp_element_["createElement"])(meta_boxes, {
+    }, Object(external_wp_element_["createElement"])(MetaBoxes, {
       location: "normal"
-    }), Object(external_wp_element_["createElement"])(meta_boxes, {
+    }), Object(external_wp_element_["createElement"])(MetaBoxes, {
       location: "advanced"
     })), isMobileViewport && sidebarIsOpened && Object(external_wp_element_["createElement"])(external_wp_components_["ScrollLock"], null)),
     footer: !hasReducedUI && showBlockBreadcrumbs && !isMobileViewport && isRichEditingEnabled && mode === 'visual' && Object(external_wp_element_["createElement"])("div", {
@@ -18306,7 +18375,6 @@ function PluginSidebarMoreMenuItem(props) {
 
 
 
-
 /**
  * Reinitializes the editor after the user chooses to reboot the editor after
  * an unhandled error occurs, replacing previously mounted editor element using
@@ -18336,11 +18404,8 @@ function reinitializeEditor(postType, postId, target, settings, initialEdits) {
 /**
  * Initializes and returns an instance of Editor.
  *
- * The return value of this function is not necessary if we change where we
- * call initializeEditor(). This is due to metaBox timing.
- *
  * @param {string}  id           Unique identifier for editor instance.
- * @param {Object}  postType     Post type of the post to edit.
+ * @param {string}  postType     Post type of the post to edit.
  * @param {Object}  postId       ID of the post to edit.
  * @param {?Object} settings     Editor settings object.
  * @param {Object}  initialEdits Programmatic edits to apply initially, to be
@@ -18410,6 +18475,7 @@ function initializeEditor(id, postType, postId, settings, initialEdits) {
 
 
 
+
 /***/ }),
 
 /***/ "g56x":

wp-includes/js/dist/edit-widgets.js

@@ -110,6 +110,13 @@ const blockDefault = Object(_wordpress_element__WEBPACK_IMPORTED_MODULE_0__["cre
 /* harmony default export */ __webpack_exports__["a"] = (blockDefault);
 
 
+/***/ }),
+
+/***/ "1CF3":
+/***/ (function(module, exports) {
+
+(function() { module.exports = window["wp"]["dom"]; }());
+
 /***/ }),
 
 /***/ "1ZqX":
@@ -161,6 +168,7 @@ const cog = Object(_wordpress_element__WEBPACK_IMPORTED_MODULE_0__["createElemen
 __webpack_require__.r(__webpack_exports__);
 
 // EXPORTS
+__webpack_require__.d(__webpack_exports__, "reinitializeEditor", function() { return /* binding */ reinitializeEditor; });
 __webpack_require__.d(__webpack_exports__, "initialize", function() { return /* binding */ initialize; });
 
 // NAMESPACE OBJECT: ./node_modules/@wordpress/edit-widgets/build-module/store/actions.js
@@ -197,6 +205,7 @@ __webpack_require__.d(selectors_namespaceObject, "getReferenceWidgetBlocks", fun
 __webpack_require__.d(selectors_namespaceObject, "isSavingWidgetAreas", function() { return selectors_isSavingWidgetAreas; });
 __webpack_require__.d(selectors_namespaceObject, "getIsWidgetAreaOpen", function() { return getIsWidgetAreaOpen; });
 __webpack_require__.d(selectors_namespaceObject, "isInserterOpened", function() { return selectors_isInserterOpened; });
+__webpack_require__.d(selectors_namespaceObject, "__experimentalGetInsertionPoint", function() { return __experimentalGetInsertionPoint; });
 __webpack_require__.d(selectors_namespaceObject, "canInsertBlockInWidgetArea", function() { return selectors_canInsertBlockInWidgetArea; });
 __webpack_require__.d(selectors_namespaceObject, "__unstableIsFeatureActive", function() { return __unstableIsFeatureActive; });
 
@@ -1247,6 +1256,24 @@ const getIsWidgetAreaOpen = (state, clientId) => {
 function selectors_isInserterOpened(state) {
   return !!state.blockInserterPanel;
 }
+/**
+ * Get the insertion point for the inserter.
+ *
+ * @param {Object} state Global application state.
+ *
+ * @return {Object} The root client ID and index to insert at.
+ */
+
+function __experimentalGetInsertionPoint(state) {
+  const {
+    rootClientId,
+    insertionIndex
+  } = state.blockInserterPanel;
+  return {
+    rootClientId,
+    insertionIndex
+  };
+}
 /**
  * Returns true if a block can be inserted into a widget area.
  *
@@ -1691,6 +1718,72 @@ const widget_area_settings = {
 // EXTERNAL MODULE: external ["wp","plugins"]
 var external_wp_plugins_ = __webpack_require__("TvNi");
 
+// CONCATENATED MODULE: ./node_modules/@wordpress/edit-widgets/build-module/components/error-boundary/index.js
+
+
+/**
+ * WordPress dependencies
+ */
+
+
+
+
+
+
+function CopyButton({
+  text,
+  children
+}) {
+  const ref = Object(external_wp_compose_["useCopyToClipboard"])(text);
+  return Object(external_wp_element_["createElement"])(external_wp_components_["Button"], {
+    variant: "secondary",
+    ref: ref
+  }, children);
+}
+
+class error_boundary_ErrorBoundary extends external_wp_element_["Component"] {
+  constructor() {
+    super(...arguments);
+    this.reboot = this.reboot.bind(this);
+    this.state = {
+      error: null
+    };
+  }
+
+  componentDidCatch(error) {
+    this.setState({
+      error
+    });
+  }
+
+  reboot() {
+    this.props.onError();
+  }
+
+  render() {
+    const {
+      error
+    } = this.state;
+
+    if (!error) {
+      return this.props.children;
+    }
+
+    return Object(external_wp_element_["createElement"])(external_wp_blockEditor_["Warning"], {
+      className: "edit-widgets-error-boundary",
+      actions: [Object(external_wp_element_["createElement"])(external_wp_components_["Button"], {
+        key: "recovery",
+        onClick: this.reboot,
+        variant: "secondary"
+      }, Object(external_wp_i18n_["__"])('Attempt Recovery')), Object(external_wp_element_["createElement"])(CopyButton, {
+        key: "copy-error",
+        text: error.stack
+      }, Object(external_wp_i18n_["__"])('Copy Error'))]
+    }, Object(external_wp_i18n_["__"])('The editor has encountered an unexpected error.'));
+  }
+
+}
+
 // EXTERNAL MODULE: ./node_modules/@babel/runtime/helpers/esm/extends.js
 var esm_extends = __webpack_require__("wx14");
 
@@ -1974,6 +2067,9 @@ var block_default = __webpack_require__("//Lo");
 // EXTERNAL MODULE: external ["wp","url"]
 var external_wp_url_ = __webpack_require__("Mmq9");
 
+// EXTERNAL MODULE: external ["wp","dom"]
+var external_wp_dom_ = __webpack_require__("1CF3");
+
 // CONCATENATED MODULE: ./node_modules/@wordpress/edit-widgets/build-module/components/sidebar/widget-areas.js
 
 
@@ -1987,6 +2083,7 @@ var external_wp_url_ = __webpack_require__("Mmq9");
 
 
 
+
 /**
  * Internal dependencies
  */
@@ -2013,7 +2110,15 @@ function WidgetAreas({
     className: "edit-widgets-widget-areas__top-container"
   }, Object(external_wp_element_["createElement"])(external_wp_blockEditor_["BlockIcon"], {
     icon: block_default["a" /* default */]
-  }), Object(external_wp_element_["createElement"])("div", null, Object(external_wp_element_["createElement"])("p", null, description), (widgetAreas === null || widgetAreas === void 0 ? void 0 : widgetAreas.length) === 0 && Object(external_wp_element_["createElement"])("p", null, Object(external_wp_i18n_["__"])('Your theme does not contain any Widget Areas.')), !selectedWidgetArea && Object(external_wp_element_["createElement"])(external_wp_components_["Button"], {
+  }), Object(external_wp_element_["createElement"])("div", null, Object(external_wp_element_["createElement"])("p", {
+    // Use `dangerouslySetInnerHTML` to keep backwards
+    // compatibility. Basic markup in the description is an
+    // established feature of WordPress.
+    // @see https://github.com/WordPress/gutenberg/issues/33106
+    dangerouslySetInnerHTML: {
+      __html: Object(external_wp_dom_["safeHTML"])(description)
+    }
+  }), (widgetAreas === null || widgetAreas === void 0 ? void 0 : widgetAreas.length) === 0 && Object(external_wp_element_["createElement"])("p", null, Object(external_wp_i18n_["__"])('Your theme does not contain any Widget Areas.')), !selectedWidgetArea && Object(external_wp_element_["createElement"])(external_wp_components_["Button"], {
     href: Object(external_wp_url_["addQueryArgs"])('customize.php', {
       'autofocus[panel]': 'widgets',
       return: window.location.pathname
@@ -2663,7 +2768,7 @@ function MoreMenu() {
   }), Object(external_wp_element_["createElement"])(external_wp_components_["MenuItem"], {
     role: "menuitem",
     icon: external["a" /* default */],
-    href: Object(external_wp_i18n_["__"])('https://wordpress.org/support/article/wordpress-editor/'),
+    href: Object(external_wp_i18n_["__"])('https://wordpress.org/support/article/block-based-widgets-editor/'),
     target: "_blank",
     rel: "noopener noreferrer"
   }, Object(external_wp_i18n_["__"])('Help'), Object(external_wp_element_["createElement"])(external_wp_components_["VisuallyHidden"], {
@@ -2893,6 +2998,7 @@ function WidgetAreasBlockEditorContent({
 
 
 
+
 const useWidgetLibraryInsertionPoint = () => {
   const firstRootId = Object(external_wp_data_["useSelect"])(select => {
     var _widgetAreasPost$bloc;
@@ -2911,6 +3017,15 @@ const useWidgetLibraryInsertionPoint = () => {
       getBlockOrder,
       getBlockIndex
     } = select(external_wp_blockEditor_["store"]);
+
+    const insertionPoint = select(store).__experimentalGetInsertionPoint(); // "Browse all" in the quick inserter will set the rootClientId to the current block.
+    // Otherwise, it will just be undefined, and we'll have to handle it differently below.
+
+
+    if (insertionPoint.rootClientId) {
+      return insertionPoint;
+    }
+
     const clientId = getBlockSelectionEnd() || firstRootId;
     const rootClientId = getBlockRootClientId(clientId); // If the selected block is at the root level, it's a widget area and
     // blocks can't be inserted here. Return this block as the root and the
@@ -3233,14 +3348,18 @@ function WelcomeGuideImage({
 
 
 
+
 function Layout({
-  blockEditorSettings
+  blockEditorSettings,
+  onError
 }) {
-  return Object(external_wp_element_["createElement"])(WidgetAreasBlockEditorProvider, {
+  return Object(external_wp_element_["createElement"])(error_boundary_ErrorBoundary, {
+    onError: onError
+  }, Object(external_wp_element_["createElement"])(WidgetAreasBlockEditorProvider, {
     blockEditorSettings: blockEditorSettings
   }, Object(external_wp_element_["createElement"])(layout_interface, {
     blockEditorSettings: blockEditorSettings
-  }), Object(external_wp_element_["createElement"])(Sidebar, null), Object(external_wp_element_["createElement"])(external_wp_components_["Popover"].Slot, null), Object(external_wp_element_["createElement"])(external_wp_plugins_["PluginArea"], null), Object(external_wp_element_["createElement"])(UnsavedChangesWarning, null), Object(external_wp_element_["createElement"])(WelcomeGuide, null));
+  }), Object(external_wp_element_["createElement"])(Sidebar, null), Object(external_wp_element_["createElement"])(external_wp_components_["Popover"].Slot, null), Object(external_wp_element_["createElement"])(external_wp_plugins_["PluginArea"], null), Object(external_wp_element_["createElement"])(UnsavedChangesWarning, null), Object(external_wp_element_["createElement"])(WelcomeGuide, null)));
 }
 
 /* harmony default export */ var layout = (Layout);
@@ -3266,6 +3385,23 @@ function Layout({
 
 
 const disabledBlocks = ['core/more', 'core/freeform', ...(!ALLOW_REUSABLE_BLOCKS && ['core/block'])];
+/**
+ * Reinitializes the editor after the user chooses to reboot the editor after
+ * an unhandled error occurs, replacing previously mounted editor element using
+ * an initial state from prior to the crash.
+ *
+ * @param {Element} target   DOM node in which editor is rendered.
+ * @param {?Object} settings Editor settings object.
+ */
+
+function reinitializeEditor(target, settings) {
+  Object(external_wp_element_["unmountComponentAtNode"])(target);
+  const reboot = reinitializeEditor.bind(null, target, settings);
+  Object(external_wp_element_["render"])(Object(external_wp_element_["createElement"])(layout, {
+    blockEditorSettings: settings,
+    onError: reboot
+  }), target);
+}
 /**
  * Initializes the block editor in the widgets screen.
  *
@@ -3274,6 +3410,9 @@ const disabledBlocks = ['core/more', 'core/freeform', ...(!ALLOW_REUSABLE_BLOCKS
  */
 
 function initialize(id, settings) {
+  const target = document.getElementById(id);
+  const reboot = reinitializeEditor.bind(null, target, settings);
+
   const coreBlocks = Object(external_wp_blockLibrary_["__experimentalGetCoreBlocks"])().filter(block => {
     return !(disabledBlocks.includes(block.name) || block.name.startsWith('core/post') || block.name.startsWith('core/query') || block.name.startsWith('core/site'));
   });
@@ -3294,8 +3433,9 @@ function initialize(id, settings) {
 
   Object(external_wp_blocks_["setFreeformContentHandlerName"])('core/html');
   Object(external_wp_element_["render"])(Object(external_wp_element_["createElement"])(layout, {
-    blockEditorSettings: settings
+    blockEditorSettings: settings,
-  }), document.getElementById(id));
+    onError: reboot
+  }), target);
 }
 /**
  * Function to register an individual block.

wp-includes/js/dist/editor.js

@@ -8074,6 +8074,7 @@ const DEFAULT_QUERY = {
   per_page: MAX_MOST_USED_TERMS,
   orderby: 'count',
   order: 'desc',
+  hide_empty: true,
   _fields: 'id,name,count'
 };
 function MostUsedTerms({

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-51717';
+$wp_version = '5.9-alpha-51719';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.