Fix history state manipulation

frontend/src/components/CelexSelector/CelexSelector.tsx

@@ -17,6 +17,9 @@ function CelexSelector() {
           setArticleId(1);
         }}
       >
+        <option value="" disabled>
+          Select an example
+        </option>
         {examples.map((example) => (
           <option key={example.id} value={example.id}>
             {example.name}

frontend/src/hooks/urlSync.ts

@@ -30,7 +30,7 @@ export const useUrlSync = () => {
 
   // Update the URL when Zustand changes
   useEffect(() => {
-    if (celexId === null) {
+    if (!celexId) {
       return;
     }
     let targetUrl = `/${celexId}`;

frontend/src/pages/MainView.tsx

@@ -4,7 +4,7 @@ import useNavStore from "../store/navStore";
 
 function MainView() {
   useUrlSync();
-  const celexId = useNavStore((state) => state.celexId);
+  const celexId = useNavStore.use.celexId();
 
   if (!celexId) {
     return <div>Error: No CELEX ID provided</div>;