diff --git a/custom-elements-manifest.config.js b/custom-elements-manifest.config.js
index 3e33bc02..a434d675 100644
--- a/custom-elements-manifest.config.js
+++ b/custom-elements-manifest.config.js
@@ -38,6 +38,7 @@ export default {
         customElementsManifest.package = { name, description, version, author, homepage, license };
       }
     },
+
     // Infer tag names because we no longer use @customElement decorators.
     {
       name: 'shoelace-infer-tag-names',
@@ -66,6 +67,7 @@ export default {
         }
       }
     },
+
     // Parse custom jsDoc tags
     {
       name: 'shoelace-custom-tags',
@@ -137,6 +139,7 @@ export default {
         }
       }
     },
+
     {
       name: 'shoelace-react-event-names',
       analyzePhase({ ts, node, moduleDoc }) {
@@ -155,6 +158,7 @@ export default {
         }
       }
     },
+
     {
       name: 'shoelace-translate-module-paths',
       packageLinkPhase({ customElementsManifest }) {
@@ -191,6 +195,7 @@ export default {
         });
       }
     },
+
     // Generate custom VS Code data
     customElementVsCodePlugin({
       outdir,
@@ -202,6 +207,7 @@ export default {
         }
       ]
     }),
+
     customElementJetBrainsPlugin({
       outdir: './dist',
       excludeCss: true,
diff --git a/docs/_includes/component.njk b/docs/_includes/component.njk
index 8b087b89..e377e692 100644
--- a/docs/_includes/component.njk
+++ b/docs/_includes/component.njk
@@ -160,7 +160,7 @@
             </td>
             <td>
               {% if prop.type.text %}
-                <code>{{ prop.type.text | markdownInline | safe }}</code>
+                <code>{{ prop.type.text | trimPipes | markdownInline | safe }}</code>
               {% else %}
                 -
               {% endif %}
@@ -211,7 +211,7 @@
             <td>{{ event.description | markdownInline | safe }}</td>
             <td>
               {% if event.type.text %}
-                <code>{{ event.type.text }}</code>
+                <code>{{ event.type.text | trimPipes  }}</code>
               {% else %}
                 -
               {% endif %}
@@ -245,7 +245,7 @@
               {% if method.parameters.length %}
                 <code>
                   {% for param in method.parameters %}
-                    {{ param.name }}: {{ param.type.text }}{% if not loop.last %},{% endif %}
+                    {{ param.name }}: {{ param.type.text | trimPipes }}{% if not loop.last %},{% endif %}
                   {% endfor %}
                 </code>
               {% else %}
diff --git a/docs/eleventy.config.cjs b/docs/eleventy.config.cjs
index 2377943f..4ca4cbd4 100644
--- a/docs/eleventy.config.cjs
+++ b/docs/eleventy.config.cjs
@@ -96,6 +96,12 @@ module.exports = function (eleventyConfig) {
     return shoelaceFlavoredMarkdown.renderInline(content);
   });
 
+  // Trims whitespace and pipes from the start and end of a string. Useful for CEM types, which can be pipe-delimited.
+  // With Prettier 3, this means a leading pipe will exist if the line wraps.
+  eleventyConfig.addFilter('trimPipes', content => {
+    return typeof content === 'string' ? content.replace(/^(\s|\|)/g, '').replace(/(\s|\|)$/g, '') : content;
+  });
+
   eleventyConfig.addFilter('classNameToComponentName', className => {
     let name = capitalCase(className.replace(/^Sl/, ''));
     if (name === 'Qr Code') name = 'QR Code'; // manual override
diff --git a/docs/pages/components/menu-item.md b/docs/pages/components/menu-item.md
index ef80dfbb..b5098843 100644
--- a/docs/pages/components/menu-item.md
+++ b/docs/pages/components/menu-item.md
@@ -60,35 +60,6 @@ const App = () => (
 
 ## Examples
 
-### Disabled
-
-Add the `disabled` attribute to disable the menu item so it cannot be selected.
-
-```html:preview
-<sl-menu style="max-width: 200px;">
-  <sl-menu-item>Option 1</sl-menu-item>
-  <sl-menu-item disabled>Option 2</sl-menu-item>
-  <sl-menu-item>Option 3</sl-menu-item>
-</sl-menu>
-```
-
-{% raw %}
-
-```jsx:react
-import SlMenu from '@shoelace-style/shoelace/dist/react/menu';
-import SlMenuItem from '@shoelace-style/shoelace/dist/react/menu-item';
-
-const App = () => (
-  <SlMenu style={{ maxWidth: '200px' }}>
-    <SlMenuItem>Option 1</SlMenuItem>
-    <SlMenuItem disabled>Option 2</SlMenuItem>
-    <SlMenuItem>Option 3</SlMenuItem>
-  </SlMenu>
-);
-```
-
-{% endraw %}
-
 ### Prefix & Suffix
 
 Add content to the start and end of menu items using the `prefix` and `suffix` slots.
@@ -151,6 +122,64 @@ const App = () => (
 
 {% endraw %}
 
+### Disabled
+
+Add the `disabled` attribute to disable the menu item so it cannot be selected.
+
+```html:preview
+<sl-menu style="max-width: 200px;">
+  <sl-menu-item>Option 1</sl-menu-item>
+  <sl-menu-item disabled>Option 2</sl-menu-item>
+  <sl-menu-item>Option 3</sl-menu-item>
+</sl-menu>
+```
+
+{% raw %}
+
+```jsx:react
+import SlMenu from '@shoelace-style/shoelace/dist/react/menu';
+import SlMenuItem from '@shoelace-style/shoelace/dist/react/menu-item';
+
+const App = () => (
+  <SlMenu style={{ maxWidth: '200px' }}>
+    <SlMenuItem>Option 1</SlMenuItem>
+    <SlMenuItem disabled>Option 2</SlMenuItem>
+    <SlMenuItem>Option 3</SlMenuItem>
+  </SlMenu>
+);
+```
+
+{% endraw %}
+
+### Loading
+
+Use the `loading` attribute to indicate that a menu item is busy. Like a disabled menu item, clicks will be suppressed until the loading state is removed.
+
+```html:preview
+<sl-menu style="max-width: 200px;">
+  <sl-menu-item>Option 1</sl-menu-item>
+  <sl-menu-item loading>Option 2</sl-menu-item>
+  <sl-menu-item>Option 3</sl-menu-item>
+</sl-menu>
+```
+
+{% raw %}
+
+```jsx:react
+import SlMenu from '@shoelace-style/shoelace/dist/react/menu';
+import SlMenuItem from '@shoelace-style/shoelace/dist/react/menu-item';
+
+const App = () => (
+  <SlMenu style={{ maxWidth: '200px' }}>
+    <SlMenuItem>Option 1</SlMenuItem>
+    <SlMenuItem loading>Option 2</SlMenuItem>
+    <SlMenuItem>Option 3</SlMenuItem>
+  </SlMenu>
+);
+```
+
+{% endraw %}
+
 ### Checkbox Menu Items
 
 Set the `type` attribute to `checkbox` to create a menu item that will toggle on and off when selected. You can use the `checked` attribute to set the initial state.
diff --git a/docs/pages/resources/changelog.md b/docs/pages/resources/changelog.md
index ad6ae558..67b420a0 100644
--- a/docs/pages/resources/changelog.md
+++ b/docs/pages/resources/changelog.md
@@ -14,10 +14,12 @@ New versions of Shoelace are released as-needed and generally occur when a criti
 
 ## Next
 
+- Added the `loading` attribute and the `spinner` and `spinner__base` part to `<sl-menu-item>` [#1700]
 - Fixed focus trapping not scrolling elements into view. [#1750]
 - Fixed more performance issues with focus trapping performance. [#1750]
 - Added the `hover-bridge` feature to `<sl-popup>` to support better tooltip accessibility [#1734]
 - Fixed a bug in `<sl-input>` and `<sl-textarea>` that made it work differently from `<input>` and `<textarea>` when using defaults [#1746]
+- Fixed a bug in `<sl-select>` that prevented it from closing when tabbing to another select inside a shadow root [#1763]
 - Improved the accessibility of `<sl-tooltip>` so they persist when hovering over the tooltip and dismiss when pressing [[Esc]] [#1734]
 
 ## 2.12.0
diff --git a/scripts/make-themes.js b/scripts/make-themes.js
index eb4c12ac..74068883 100644
--- a/scripts/make-themes.js
+++ b/scripts/make-themes.js
@@ -47,9 +47,19 @@ files.forEach(async file => {
     { parser: 'babel-ts' }
   );
 
+  let dTs = await prettier.format(
+    `
+    declare const _default: import("lit").CSSResult;
+    export default _default;
+  `,
+    { parser: 'babel-ts' }
+  );
+
   const cssFile = path.join(themesDir, path.basename(file));
   const jsFile = path.join(themesDir, path.basename(file).replace('.css', '.styles.js'));
+  const dTsFile = path.join(themesDir, path.basename(file).replace('.css', '.styles.d.ts'));
 
   fs.writeFileSync(cssFile, css, 'utf8');
   fs.writeFileSync(jsFile, js, 'utf8');
+  fs.writeFileSync(dTsFile, dTs, 'utf8');
 });
diff --git a/src/components/menu-item/menu-item.component.ts b/src/components/menu-item/menu-item.component.ts
index ebb92eef..adb492b7 100644
--- a/src/components/menu-item/menu-item.component.ts
+++ b/src/components/menu-item/menu-item.component.ts
@@ -8,6 +8,7 @@ import { watch } from '../../internal/watch.js';
 import ShoelaceElement from '../../internal/shoelace-element.js';
 import SlIcon from '../icon/icon.component.js';
 import SlPopup from '../popup/popup.component.js';
+import SlSpinner from '../spinner/spinner.component.js';
 import styles from './menu-item.styles.js';
 import type { CSSResultGroup } from 'lit';
 
@@ -19,6 +20,7 @@ import type { CSSResultGroup } from 'lit';
  *
  * @dependency sl-icon
  * @dependency sl-popup
+ * @dependency sl-spinner
  *
  * @slot - The menu item's label.
  * @slot prefix - Used to prepend an icon or similar element to the menu item.
@@ -30,6 +32,8 @@ import type { CSSResultGroup } from 'lit';
  * @csspart prefix - The prefix container.
  * @csspart label - The menu item label.
  * @csspart suffix - The suffix container.
+ * @csspart spinner - The spinner that shows when the menu item is in the loading state.
+ * @csspart spinner__base - The spinner's base part.
  * @csspart submenu-icon - The submenu icon, visible only when the menu item has a submenu (not yet implemented).
  *
  * @cssproperty [--submenu-offset=-2px] - The distance submenus shift to overlap the parent menu.
@@ -38,7 +42,8 @@ export default class SlMenuItem extends ShoelaceElement {
   static styles: CSSResultGroup = styles;
   static dependencies = {
     'sl-icon': SlIcon,
-    'sl-popup': SlPopup
+    'sl-popup': SlPopup,
+    'sl-spinner': SlSpinner
   };
 
   private cachedTextLabel: string;
@@ -55,6 +60,9 @@ export default class SlMenuItem extends ShoelaceElement {
   /** A unique value to store in the menu item. This can be used as a way to identify menu items when selected. */
   @property() value = '';
 
+  /** Draws the menu item in a loading state. */
+  @property({ type: Boolean, reflect: true }) loading = false;
+
   /** Draws the menu item in a disabled state, preventing selection. */
   @property({ type: Boolean, reflect: true }) disabled = false;
 
@@ -158,6 +166,7 @@ export default class SlMenuItem extends ShoelaceElement {
           'menu-item--rtl': isRtl,
           'menu-item--checked': this.checked,
           'menu-item--disabled': this.disabled,
+          'menu-item--loading': this.loading,
           'menu-item--has-submenu': this.isSubmenu(),
           'menu-item--submenu-expanded': isSubmenuExpanded
         })}
@@ -179,6 +188,7 @@ export default class SlMenuItem extends ShoelaceElement {
         </span>
 
         ${this.submenuController.renderSubmenu()}
+        ${this.loading ? html` <sl-spinner part="spinner" exportparts="base:spinner__base"></sl-spinner> ` : ''}
       </div>
     `;
   }
diff --git a/src/components/menu-item/menu-item.styles.ts b/src/components/menu-item/menu-item.styles.ts
index 14fe5aa1..499adecc 100644
--- a/src/components/menu-item/menu-item.styles.ts
+++ b/src/components/menu-item/menu-item.styles.ts
@@ -38,6 +38,25 @@ export default css`
     cursor: not-allowed;
   }
 
+  .menu-item.menu-item--loading {
+    outline: none;
+    cursor: wait;
+  }
+
+  .menu-item.menu-item--loading *:not(sl-spinner) {
+    opacity: 0.5;
+  }
+
+  .menu-item--loading sl-spinner {
+    --indicator-color: currentColor;
+    --track-width: 1px;
+    position: absolute;
+    font-size: 0.75em;
+    top: calc(50% - 0.5em);
+    left: 0.65rem;
+    opacity: 1;
+  }
+
   .menu-item .menu-item__label {
     flex: 1 1 auto;
     display: inline-block;
diff --git a/src/components/menu-item/menu-item.test.ts b/src/components/menu-item/menu-item.test.ts
index abee95d8..65676e53 100644
--- a/src/components/menu-item/menu-item.test.ts
+++ b/src/components/menu-item/menu-item.test.ts
@@ -40,6 +40,7 @@ describe('<sl-menu-item>', () => {
 
     expect(el.value).to.equal('');
     expect(el.disabled).to.be.false;
+    expect(el.loading).to.equal(false);
     expect(el.getAttribute('aria-disabled')).to.equal('false');
   });
 
@@ -48,6 +49,13 @@ describe('<sl-menu-item>', () => {
     expect(el.getAttribute('aria-disabled')).to.equal('true');
   });
 
+  describe('when loading', () => {
+    it('should have a spinner present', async () => {
+      const el = await fixture<SlMenuItem>(html` <sl-menu-item loading>Menu Item Label</sl-menu-item> `);
+      expect(el.shadowRoot!.querySelector('sl-spinner')).to.exist;
+    });
+  });
+
   it('should return a text label when calling getTextLabel()', async () => {
     const el = await fixture<SlMenuItem>(html` <sl-menu-item>Test</sl-menu-item> `);
     expect(el.getTextLabel()).to.equal('Test');
diff --git a/src/components/select/select.component.ts b/src/components/select/select.component.ts
index b8a01102..14c830d3 100644
--- a/src/components/select/select.component.ts
+++ b/src/components/select/select.component.ts
@@ -216,15 +216,22 @@ export default class SlSelect extends ShoelaceElement implements ShoelaceFormCon
   }
 
   private addOpenListeners() {
-    document.addEventListener('focusin', this.handleDocumentFocusIn);
-    document.addEventListener('keydown', this.handleDocumentKeyDown);
-    document.addEventListener('mousedown', this.handleDocumentMouseDown);
+    //
+    // Listen on the root node instead of the document in case the elements are inside a shadow root
+    //
+    // https://github.com/shoelace-style/shoelace/issues/1763
+    //
+    const root = this.getRootNode();
+    root.addEventListener('focusin', this.handleDocumentFocusIn);
+    root.addEventListener('keydown', this.handleDocumentKeyDown);
+    root.addEventListener('mousedown', this.handleDocumentMouseDown);
   }
 
   private removeOpenListeners() {
-    document.removeEventListener('focusin', this.handleDocumentFocusIn);
-    document.removeEventListener('keydown', this.handleDocumentKeyDown);
-    document.removeEventListener('mousedown', this.handleDocumentMouseDown);
+    const root = this.getRootNode();
+    root.removeEventListener('focusin', this.handleDocumentFocusIn);
+    root.removeEventListener('keydown', this.handleDocumentKeyDown);
+    root.removeEventListener('mousedown', this.handleDocumentMouseDown);
   }
 
   private handleFocus() {
diff --git a/src/components/select/select.test.ts b/src/components/select/select.test.ts
index acd4ea35..0f80a7e6 100644
--- a/src/components/select/select.test.ts
+++ b/src/components/select/select.test.ts
@@ -156,6 +156,7 @@ describe('<sl-select>', () => {
       await el.updateComplete;
       await sendKeys({ press: 'ArrowDown' }); // move selection to the third option
       await el.updateComplete;
+      el.focus(); // For some reason, the browser loses focus before we press enter. Refocus the select.
       await sendKeys({ press: 'Enter' }); // commit the selection
       await el.updateComplete;