From 510004cd8f4c0d64984f7afa398e4ef177ba7e27 Mon Sep 17 00:00:00 2001
From: A0 Orchestrator <orchestrator@media-on.de>
Date: Fri, 3 Jul 2026 21:18:13 +0200
Subject: [PATCH] =?UTF-8?q?fix:=20history/undo/redo=20=E2=80=94=20re-init?=
 =?UTF-8?q?=20after=20project=20load=20+=20sync=20to=20Yjs=20CRDT?=
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---
 frontend/src/App.tsx | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 29d3fa4..0cc4ccc 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -238,18 +238,30 @@ const CADEditor: React.FC<CADEditorProps> = ({ projectId, token, onNavigateBack
     if (snap) {
       restoreSnapshot(snap);
       syncHistory();
+      // Sync restored state to Yjs CRDT to prevent collab overwrite
+      if (collab.status === 'connected') {
+        for (const el of snap.elements) collab.setElement(el);
+        for (const layer of snap.layers) collab.setLayer(layer);
+        for (const block of snap.blocks) collab.setBlock(block);
+      }
       setCommandHistory((prev) => [...prev, { prefix: '·', text: 'Rückgängig: letzte Aktion', type: 'info' }]);
     }
-  }, [restoreSnapshot, syncHistory]);
+  }, [restoreSnapshot, syncHistory, collab]);
 
   const handleRedo = useCallback(() => {
     const snap = historyManagerRef.current.redo();
     if (snap) {
       restoreSnapshot(snap);
       syncHistory();
+      // Sync restored state to Yjs CRDT to prevent collab overwrite
+      if (collab.status === 'connected') {
+        for (const el of snap.elements) collab.setElement(el);
+        for (const layer of snap.layers) collab.setLayer(layer);
+        for (const block of snap.blocks) collab.setBlock(block);
+      }
       setCommandHistory((prev) => [...prev, { prefix: '·', text: 'Wiederherstellen: letzte Aktion', type: 'info' }]);
     }
-  }, [restoreSnapshot, syncHistory]);
+  }, [restoreSnapshot, syncHistory, collab]);
 
   const pushHistorySnapshot = useCallback((label: string) => {
     historyManagerRef.current.pushSnapshot({
@@ -318,6 +330,15 @@ const CADEditor: React.FC<CADEditorProps> = ({ projectId, token, onNavigateBack
         }
         setSavedStatus('gespeichert');
         setDataLoaded(true);
+        // Re-initialize HistoryManager with loaded project state so undo does not jump back to empty initial state
+        historyManagerRef.current.initialize({
+          elements: data.elements,
+          layers: data.layers.length > 0 ? data.layers : initialLayers,
+          blocks: data.blocks,
+          groups: [],
+          bgConfig: null,
+        });
+        syncHistory();
         // Push initial data to Yjs CRDT after load
         // Issue #7: Only push to CRDT if backend data actually has content.
         // Pushing empty arrays would wipe existing CRDT data from other connected clients.