search: respect the stored platform on non platform pages

app/not-found.tsx

@@ -24,7 +24,13 @@ export default function NotFound() {
 
         <div className="max-w-md pt-8">
           <p className="pb-4">Let's give it another shot:</p>
-          <Search autoFocus path={pathname} searchPlatforms={[]} showChatBot={false} />
+          <Search
+            autoFocus
+            path={pathname}
+            searchPlatforms={[]}
+            showChatBot={false}
+            useStoredSearchPlatforms={false}
+          />
         </div>
         <div className="pt-8 flex gap-4">
           <Button variant="solid" size="3" asChild>

src/components/header.tsx

@@ -20,9 +20,15 @@ type Props = {
   pathname: string;
   searchPlatforms: string[];
   noSearch?: boolean;
+  useStoredSearchPlatforms?: boolean;
 };
 
-export function Header({pathname, searchPlatforms, noSearch}: Props) {
+export function Header({
+  pathname,
+  searchPlatforms,
+  noSearch,
+  useStoredSearchPlatforms,
+}: Props) {
   return (
     <header className="bg-[var(--gray-1)] h-[var(--header-height)] w-full z-50 border-b border-[var(--gray-a3)] fixed top-0">
       {/* define a header-height variable for consumption by other components */}
@@ -62,7 +68,12 @@ export function Header({pathname, searchPlatforms, noSearch}: Props) {
         </Link>
         {!noSearch && (
           <div className="hidden md:flex justify-center lg:justify-start w-full px-6">
-            <Search path={pathname} searchPlatforms={searchPlatforms} showChatBot />
+            <Search
+              path={pathname}
+              searchPlatforms={searchPlatforms}
+              showChatBot
+              useStoredSearchPlatforms={useStoredSearchPlatforms}
+            />
           </div>
         )}
         <div className="hidden lg-xl:flex justify-end flex-1 space-x-2 items-center min-w-fit">

src/components/home.tsx

@@ -21,7 +21,7 @@ import {PlatformFilter} from './platformFilter';
 export function Home() {
   return (
     <div className="tw-app">
-      <Header pathname="/" searchPlatforms={[]} />
+      <Header pathname="/" searchPlatforms={[]} useStoredSearchPlatforms={false} />
       <div className="mt-[var(--header-height)]">
         <Banner />
       </div>

src/components/search/index.tsx

@@ -62,18 +62,50 @@ type Props = {
   path?: string;
   searchPlatforms?: string[];
   showChatBot?: boolean;
+  useStoredSearchPlatforms?: boolean;
 };
 
-export function Search({path, autoFocus, searchPlatforms = [], showChatBot}: Props) {
+const STORAGE_KEY = 'sentry-docs-search-platforms';
+
+export function Search({
+  path,
+  autoFocus,
+  searchPlatforms = [],
+  showChatBot,
+  useStoredSearchPlatforms = true,
+}: Props) {
   const ref = useRef<HTMLDivElement>(null);
   const [query, setQuery] = useState(``);
   const [results, setResults] = useState([] as Result[]);
   const [inputFocus, setInputFocus] = useState(false);
   const [showOffsiteResults, setShowOffsiteResults] = useState(false);
   const [loading, setLoading] = useState(true);
-
+  const [currentSearchPlatforms, setCurrentSearchPlatforms] = useState(searchPlatforms);
   const pathname = usePathname();
 
+  // Load stored platforms on mount
+  useEffect(() => {
+    const storedPlatforms = localStorage.getItem(STORAGE_KEY) ?? '[]';
+    if (!storedPlatforms) {
+      localStorage.setItem(STORAGE_KEY, JSON.stringify(searchPlatforms));
+    } else if (
+      storedPlatforms &&
+      searchPlatforms.length === 0 &&
+      useStoredSearchPlatforms
+    ) {
+      const platforms = JSON.parse(storedPlatforms);
+      setCurrentSearchPlatforms(platforms);
+    }
+  }, [useStoredSearchPlatforms, searchPlatforms]);
+
+  // Update stored platforms when they change
+  useEffect(() => {
+    if (searchPlatforms.length > 0) {
+      localStorage.setItem(STORAGE_KEY, JSON.stringify(searchPlatforms));
+      setCurrentSearchPlatforms(searchPlatforms);
+    }
+  }, [searchPlatforms]);
+
   const handleClickOutside = useCallback((ev: MouseEvent) => {
     // don't close the search results if the user is clicking the expand button
     if (
@@ -143,7 +175,7 @@ export function Search({path, autoFocus, searchPlatforms = [], showChatBot}: Pro
         inputQuery,
         {
           path,
-          platforms: searchPlatforms.map(
+          platforms: currentSearchPlatforms.map(
             platform => standardSDKSlug(platform)?.slug ?? ''
           ),
           searchAllIndexes: showOffsiteResults,
@@ -163,7 +195,7 @@ export function Search({path, autoFocus, searchPlatforms = [], showChatBot}: Pro
         setResults(queryResults);
       }
     },
-    [path, searchPlatforms, showOffsiteResults, loading]
+    [path, currentSearchPlatforms, showOffsiteResults, loading]
   );
 
   const totalHits = results.reduce((a, x) => a + x.hits.length, 0);