frontend/src/features/workspace/WorkspaceView.tsx

@@ -132,6 +132,7 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
   // Dedicated WebSocket connection & status for live indicator
   const wsRef = useRef<WebSocket | null>(null);
   const wsReconnectTimerRef = useRef<any>(null);
+  const wsReconnectDelayRef = useRef<number>(2000);
   const [wsConnected, setWsConnected] = useState<boolean>(false);
 
   // Folder state (synchronized with server)
@@ -970,6 +971,7 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
 
         ws.onopen = () => {
           if (!isMounted) return;
+          wsReconnectDelayRef.current = 2000;
           setWsConnected(true);
           api.getFolders().then(setCustomFolders).catch(() => {});
           api.getSharedFolders().then(setSharedFolders).catch(() => {});
@@ -979,7 +981,9 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
           if (!isMounted) return;
           setWsConnected(false);
           clearTimeout(wsReconnectTimerRef.current);
-          wsReconnectTimerRef.current = setTimeout(connect, 2000);
+          const delay = wsReconnectDelayRef.current;
+          wsReconnectDelayRef.current = Math.min(30000, Math.round(wsReconnectDelayRef.current * 1.5));
+          wsReconnectTimerRef.current = setTimeout(connect, delay);
         };
 
         ws.onerror = () => {
@@ -997,7 +1001,9 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
         if (!isMounted) return;
         setWsConnected(false);
         clearTimeout(wsReconnectTimerRef.current);
-        wsReconnectTimerRef.current = setTimeout(connect, 3000);
+        const delay = wsReconnectDelayRef.current;
+        wsReconnectDelayRef.current = Math.min(30000, Math.round(wsReconnectDelayRef.current * 1.5));
+        wsReconnectTimerRef.current = setTimeout(connect, delay);
       }
     };
 
@@ -1024,6 +1030,44 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
     };
   }, [onStatsChange]);
 
+  // Fallback HTTP polling when WebSocket is disconnected (e.g. corporate proxy / firewall blocking WebSockets)
+  useEffect(() => {
+    if (wsConnected) return;
+
+    let isMounted = true;
+    const pollInterval = setInterval(async () => {
+      if (!isMounted || document.visibilityState !== 'visible') return;
+
+      // 1. Poll lock status of currently selected document
+      if (selectedDocIdRef.current) {
+        try {
+          const res = await api.getDocLock(selectedDocIdRef.current);
+          if (res.locked && res.lock && res.lock.userId !== currentUserIdRef.current) {
+            setActiveLock(res.lock);
+          } else {
+            setActiveLock(null);
+          }
+        } catch {}
+      }
+
+      // 2. Poll document content if not actively typing and document has changed on server
+      if (selectedDocIdRef.current && !isEditorFocusedRef.current && !pendingSaveDocRef.current) {
+        try {
+          const fresh = await api.getDocument(selectedDocIdRef.current);
+          if (fresh && (!selectedDoc || fresh.updatedAt !== selectedDoc.updatedAt)) {
+            setSelectedDoc(fresh);
+            setDocs((prev) => prev.map((d) => (d.id === fresh.id ? fresh : d)));
+          }
+        } catch {}
+      }
+    }, 4000);
+
+    return () => {
+      isMounted = false;
+      clearInterval(pollInterval);
+    };
+  }, [wsConnected, selectedDoc?.updatedAt]);
+
   const openShareModal = async () => {
     if (!selectedDoc) return;
     setShowShareModal(true);
@@ -4001,11 +4045,15 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
             className={`h-8 w-8 flex items-center justify-center rounded-btn border transition-colors ${
               wsConnected
                 ? 'bg-emerald-500/10 border-emerald-500/30 text-emerald-500'
-                : 'bg-canvas border-border text-muted'
+                : 'bg-amber-500/10 border-amber-500/30 text-amber-500'
             }`}
-            title={wsConnected ? 'Live synchronisiert (Online)' : 'Offline - Verbindung wird wiederhergestellt'}
+            title={
+              wsConnected
+                ? 'Live synchronisiert (WebSocket online)'
+                : 'Proxy/Offline-Fallback: Synchronisation über HTTP aktiv'
+            }
           >
-            <Radio className={`w-3.5 h-3.5 ${wsConnected ? 'animate-pulse' : ''}`} />
+            <Radio className={`w-3.5 h-3.5 ${wsConnected ? 'animate-pulse' : 'opacity-80'}`} />
           </div>
         </div>
       </div>
@@ -4037,11 +4085,15 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
             className={`h-9 w-9 flex items-center justify-center rounded-btn border transition-colors ${
               wsConnected
                 ? 'bg-emerald-500/10 border-emerald-500/30 text-emerald-500'
-                : 'bg-canvas border-border text-muted'
+                : 'bg-amber-500/10 border-amber-500/30 text-amber-500'
             }`}
-            title={wsConnected ? 'Live synchronisiert (Online)' : 'Offline - Verbindung wird wiederhergestellt'}
+            title={
+              wsConnected
+                ? 'Live synchronisiert (WebSocket online)'
+                : 'Proxy/Offline-Fallback: Synchronisation über HTTP aktiv'
+            }
           >
-            <Radio className={`w-3.5 h-3.5 ${wsConnected ? 'animate-pulse' : ''}`} />
+            <Radio className={`w-3.5 h-3.5 ${wsConnected ? 'animate-pulse' : 'opacity-80'}`} />
           </div>
         </div>
       </div>

frontend/src/lib/api.ts

@@ -1048,6 +1048,7 @@ let wsListeners: ((msg: WSMessage) => void)[] = [];
 let wsStatusListeners: ((connected: boolean) => void)[] = [];
 let isWSConnected = false;
 let manualDisconnect = false;
+let wsReconnectDelay = 2000;
 
 export function buildWebSocketURL(listId?: string): string {
   const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
@@ -1097,6 +1098,7 @@ export function connectWebSocket(): void {
     activeGlobalWS = ws;
 
     ws.onopen = () => {
+      wsReconnectDelay = 2000;
       notifyStatusChange(true);
     };
 
@@ -1121,9 +1123,11 @@ export function connectWebSocket(): void {
       notifyStatusChange(false);
       if (!manualDisconnect && getToken()) {
         clearTimeout(wsReconnectTimer);
+        const delay = wsReconnectDelay;
+        wsReconnectDelay = Math.min(30000, Math.round(wsReconnectDelay * 1.5));
         wsReconnectTimer = setTimeout(() => {
           connectWebSocket();
-        }, 3000);
+        }, delay);
       }
     };