[Serverless Nav] Fix issues with sticky app menu subheader (#168372)

## Summary

- Fixes sticky kql bar in serverless security project
https://github.com/elastic/kibana/issues/167908
- Fixes double scroll in serverless discover caused by incorrect app
container height cc @elastic/kibana-data-discovery

![Screenshot 2023-10-10 at 17 23
58](3bf50299-7d9f-4c38-953a-33a6a75815c6)

- Fixes empty app header for top_nav component, for example, discover
doc page:

![Screenshot 2023-10-10 at 17 24
45](4965deac-9472-402f-8e8e-66ede83ce1bb)

---------
Co-authored-by: Cee Chen <constance.chen@elastic.co>

packages/core/chrome/core-chrome-browser-internal/src/chrome_service.tsx

@@ -203,14 +203,20 @@ export class ChromeService {
     };
 
     const headerBanner$ = new BehaviorSubject<ChromeUserBanner | undefined>(undefined);
-    const bodyClasses$ = combineLatest([headerBanner$, this.isVisible$!, chromeStyle$]).pipe(
-      map(([headerBanner, isVisible, chromeStyle]) => {
+    const bodyClasses$ = combineLatest([
+      headerBanner$,
+      this.isVisible$!,
+      chromeStyle$,
+      application.currentActionMenu$,
+    ]).pipe(
+      map(([headerBanner, isVisible, chromeStyle, actionMenu]) => {
         return [
           'kbnBody',
           headerBanner ? 'kbnBody--hasHeaderBanner' : 'kbnBody--noHeaderBanner',
           isVisible ? 'kbnBody--chromeVisible' : 'kbnBody--chromeHidden',
+          chromeStyle === 'project' && actionMenu ? 'kbnBody--hasProjectActionMenu' : '',
           getKbnVersionClass(),
-        ];
+        ].filter((className) => !!className);
       })
     );
 

packages/core/chrome/core-chrome-browser-internal/src/ui/project/app_menu.tsx

@@ -17,6 +17,7 @@ interface AppMenuBarProps {
 }
 export const AppMenuBar = ({ headerActionMenuMounter }: AppMenuBarProps) => {
   const { euiTheme } = useEuiTheme();
+
   return (
     <div
       className="header__actionMenu"
@@ -28,7 +29,8 @@ export const AppMenuBar = ({ headerActionMenuMounter }: AppMenuBarProps) => {
         display: flex;
         justify-content: end;
         align-items: center;
-        padding: ${euiTheme.size.s};
+        padding: 0 ${euiTheme.size.s};
+        height: var(--kbnProjectHeaderAppActionMenuHeight, ${euiTheme.size.xxxl});
         margin-bottom: -${euiTheme.border.width.thin};
         /* fixates the elements position in the viewport, removes the element from the flow of the page */
         position: sticky;

packages/react/kibana_mount/mount_point_portal.test.tsx

@@ -58,6 +58,23 @@ describe('MountPointPortal', () => {
     expect(setMountPoint).toHaveBeenCalledTimes(1);
   });
 
+  it('calls the provided `setMountPoint` with undefined during unmount', async () => {
+    dom = mount(
+      <MountPointPortal setMountPoint={setMountPoint}>
+        <span>portal content</span>
+      </MountPointPortal>
+    );
+
+    await refresh();
+
+    dom.unmount();
+
+    await refresh();
+
+    expect(setMountPoint).toHaveBeenCalledTimes(2);
+    expect(setMountPoint).toHaveBeenLastCalledWith(undefined);
+  });
+
   it('renders the portal content when calling the mountPoint ', async () => {
     dom = mount(
       <MountPointPortal setMountPoint={setMountPoint}>
@@ -127,7 +144,7 @@ describe('MountPointPortal', () => {
 
   it('updates the content of the portal element when the content of MountPointPortal changes', async () => {
     const Wrapper: FC<{
-      setMount: (mountPoint: MountPoint<HTMLElement>) => void;
+      setMount: (mountPoint: MountPoint<HTMLElement> | undefined) => void;
       portalContent: string;
     }> = ({ setMount, portalContent }) => {
       return (

packages/react/kibana_mount/mount_point_portal.tsx

@@ -13,7 +13,7 @@ import { MountPoint } from '@kbn/core/public';
 import { useIfMounted } from './utils';
 
 export interface MountPointPortalProps {
-  setMountPoint: (mountPoint: MountPoint<HTMLElement>) => void;
+  setMountPoint: (mountPoint: MountPoint<HTMLElement> | undefined) => void;
 }
 
 /**
@@ -47,6 +47,7 @@ export const MountPointPortal: React.FC<MountPointPortalProps> = ({ children, se
         setShouldRender(false);
         el.current = undefined;
       });
+      setMountPoint(undefined);
     };
   }, [setMountPoint, ifMounted]);
 

src/core/public/_css_variables.scss

@@ -5,6 +5,8 @@
   --kbnHeaderOffset: var(--euiFixedHeadersOffset, 0);
   // total height of everything when the banner is present
   --kbnHeaderOffsetWithBanner: calc(var(--kbnHeaderBannerHeight) + var(--kbnHeaderOffset));
+  // height of the action menu in the header in serverless projects
+  --kbnProjectHeaderAppActionMenuHeight: #{$euiSize * 3};
 }
 
 // Quick note: This shouldn't be mixed with Sass variable declarations,

src/core/public/_mixins.scss

@@ -1,6 +1,10 @@
 @mixin kibanaFullBodyHeight($additionalOffset: 0) {
-  // The `--euiFixedHeadersOffset` CSS variable is automatically updated by
+  // The `--kbnAppHeadersOffset` CSS variable is automatically updated by
   // styles/rendering/_base.scss, based on whether the Kibana chrome has a
-  // header banner, and is visible or hidden
-  height: calc(100vh - var(--euiFixedHeadersOffset, 0) - #{$additionalOffset});
+  // header banner, app menu, and is visible or hidden
+  height: calc(
+    100vh
+    - var(--kbnAppHeadersOffset, var(--euiFixedHeadersOffset, 0))
+    - #{$additionalOffset}
+  );
 }

src/core/public/styles/rendering/_base.scss

@@ -19,7 +19,7 @@
   pointer-events: none;
   visibility: hidden;
   position: fixed;
-  top: var(--euiFixedHeadersOffset, 0);
+  top: var(--kbnAppHeadersOffset, var(--euiFixedHeadersOffset, 0));
   right: 0;
   bottom: 0;
   left: 0;
@@ -41,7 +41,6 @@
 
 // Conditionally override :root CSS fixed header variable. Updating `--euiFixedHeadersOffset`
 // on the body will cause all child EUI components to automatically update their offsets
-
 .kbnBody--hasHeaderBanner {
   --euiFixedHeadersOffset: var(--kbnHeaderOffsetWithBanner);
 
@@ -56,9 +55,25 @@
     top: var(--kbnHeaderBannerHeight);
   }
 }
+
+// Set a body CSS variable for the app container to use - calculates the total
+// height of all fixed headers + the sticky action menu toolbar
+.kbnBody--hasProjectActionMenu {
+  --kbnAppHeadersOffset: calc(var(--kbnHeaderOffset) + var(--kbnProjectHeaderAppActionMenuHeight));
+
+  &.kbnBody--hasHeaderBanner {
+    --kbnAppHeadersOffset: calc(var(--kbnHeaderOffsetWithBanner) + var(--kbnProjectHeaderAppActionMenuHeight));
+  }
+}
+
 .kbnBody--chromeHidden {
   --euiFixedHeadersOffset: 0;
-}
-.kbnBody--chromeHidden.kbnBody--hasHeaderBanner {
-  --euiFixedHeadersOffset: var(--kbnHeaderBannerHeight);
+
+  &.kbnBody--hasHeaderBanner {
+    --euiFixedHeadersOffset: var(--kbnHeaderBannerHeight);
+  }
+
+  &.kbnBody--hasProjectActionMenu {
+    --kbnAppHeadersOffset: var(--euiFixedHeadersOffset, 0);
+  }
 }

src/plugins/kibana_react/public/index.ts

@@ -76,7 +76,7 @@ export { createNotifications } from './notifications';
 /** @deprecated use `Markdown` from `@kbn/shared-ux-markdown` */
 export { Markdown, MarkdownSimple } from './markdown';
 
-export { toMountPoint, MountPointPortal } from './util';
+export { toMountPoint } from './util';
 export type { ToMountPointOptions } from './util';
 
 /** @deprecated Use `RedirectAppLinks` from `@kbn/shared-ux-link-redirect-app` */

src/plugins/kibana_react/public/util/index.tsx

@@ -15,11 +15,7 @@ import type { I18nStart } from '@kbn/core-i18n-browser';
 import type { CoreTheme, ThemeServiceStart } from '@kbn/core-theme-browser';
 import { defaultTheme } from '@kbn/react-kibana-context-common';
 
-import {
-  toMountPoint as _toMountPoint,
-  MountPointPortal as _MountPointPortal,
-  useIfMounted as _useIfMounted,
-} from '@kbn/react-kibana-mount';
+import { toMountPoint as _toMountPoint } from '@kbn/react-kibana-mount';
 
 // The `theme` start contract should always be included to ensure
 // dark mode is applied correctly.  This code is for compatibility purposes,
@@ -52,13 +48,3 @@ export const toMountPoint = (
   const theme = theme$ ? { theme$ } : themeStart;
   return _toMountPoint(node, { theme, i18n });
 };
-
-/**
- * @deprecated use `MountPointPortal` from `@kbn/react-kibana-mount`
- */
-export const MountPointPortal = _MountPointPortal;
-
-/**
- * @deprecated use `useIfMounted` from `@kbn/react-kibana-mount`
- */
-export const useIfMounted = _useIfMounted;

src/plugins/navigation/kibana.jsonc

@@ -6,11 +6,7 @@
     "id": "navigation",
     "server": false,
     "browser": true,
-    "requiredPlugins": [
-      "unifiedSearch"
-    ],
-    "requiredBundles": [
-      "kibanaReact"
-    ]
+    "requiredPlugins": ["unifiedSearch"],
+    "requiredBundles": []
   }
 }

src/plugins/navigation/public/top_nav_menu/top_nav_menu.tsx

@@ -18,7 +18,7 @@ import {
 import classNames from 'classnames';
 
 import { MountPoint } from '@kbn/core/public';
-import { MountPointPortal } from '@kbn/kibana-react-plugin/public';
+import { MountPointPortal } from '@kbn/react-kibana-mount';
 import { UnifiedSearchPublicPluginStart } from '@kbn/unified-search-plugin/public';
 import { StatefulSearchBarProps } from '@kbn/unified-search-plugin/public';
 import { AggregateQuery, Query } from '@kbn/es-query';
@@ -138,14 +138,19 @@ export function TopNavMenu<QT extends AggregateQuery | Query = Query>(
       'kbnTopNavMenu__wrapper--hidden': visible === false,
     });
     if (setMenuMountPoint) {
+      const badgesEl = renderBadges();
+      const menuEl = renderMenu(menuClassName);
       return (
         <>
-          <MountPointPortal setMountPoint={setMenuMountPoint}>
-            <span className={`${wrapperClassName} kbnTopNavMenu__badgeWrapper`}>
-              {renderBadges()}
-              {renderMenu(menuClassName)}
-            </span>
-          </MountPointPortal>
+          {(badgesEl || menuEl) && (
+            <MountPointPortal setMountPoint={setMenuMountPoint}>
+              <span className={`${wrapperClassName} kbnTopNavMenu__badgeWrapper`}>
+                {badgesEl}
+                {menuEl}
+              </span>
+            </MountPointPortal>
+          )}
+
           {renderSearchBar()}
         </>
       );

src/plugins/navigation/tsconfig.json

@@ -6,11 +6,11 @@
   "include": ["public/**/*"],
   "kbn_references": [
     "@kbn/core",
-    "@kbn/kibana-react-plugin",
     "@kbn/unified-search-plugin",
     "@kbn/es-query",
     "@kbn/i18n-react",
     "@kbn/test-jest-helpers",
+    "@kbn/react-kibana-mount",
   ],
   "exclude": [
     "target/**/*",

x-pack/plugins/security_solution/public/app/home/template_wrapper/global_kql_header/index.tsx

@@ -12,7 +12,7 @@ import { useGlobalHeaderPortal } from '../../../../common/hooks/use_global_heade
 const StyledStickyWrapper = styled.div`
   position: sticky;
   z-index: ${(props) => props.theme.eui.euiZHeaderBelowDataGrid};
-  top: var(--euiFixedHeadersOffset, 0);
+  top: var(--kbnAppHeadersOffset, var(--euiFixedHeadersOffset, 0));
 `;
 
 export const GlobalKQLHeader = React.memo(() => {