Improve VPS delivery and simplify editor history

package-lock.json

@@ -8,6 +8,7 @@
       "name": "worldshaper",
       "version": "0.0.3",
       "dependencies": {
+        "compression": "^1.8.1",
         "express": "^4.19.2",
         "pixi.js": "^8.19.0",
         "react": "^19.2.6",
@@ -1442,6 +1443,60 @@
       ],
       "license": "CC-BY-4.0"
     },
+    "node_modules/compressible": {
+      "version": "2.0.18",
+      "resolved": "https://registry.npmjs.org/compressible/-/compressible-2.0.18.tgz",
+      "integrity": "sha512-AF3r7P5dWxL8MxyITRMlORQNaOA2IkAFaTr4k7BUumjPtRpGDTZpl0Pb1XCO6JeDCBdp126Cgs9sMxqSjgYyRg==",
+      "license": "MIT",
+      "dependencies": {
+        "mime-db": ">= 1.43.0 < 2"
+      },
+      "engines": {
+        "node": ">= 0.6"
+      }
+    },
+    "node_modules/compression": {
+      "version": "1.8.1",
+      "resolved": "https://registry.npmjs.org/compression/-/compression-1.8.1.tgz",
+      "integrity": "sha512-9mAqGPHLakhCLeNyxPkK4xVo746zQ/czLH1Ky+vkitMnWfWZps8r0qXuwhwizagCRttsL4lfG4pIOvaWLpAP0w==",
+      "license": "MIT",
+      "dependencies": {
+        "bytes": "3.1.2",
+        "compressible": "~2.0.18",
+        "debug": "2.6.9",
+        "negotiator": "~0.6.4",
+        "on-headers": "~1.1.0",
+        "safe-buffer": "5.2.1",
+        "vary": "~1.1.2"
+      },
+      "engines": {
+        "node": ">= 0.8.0"
+      }
+    },
+    "node_modules/compression/node_modules/debug": {
+      "version": "2.6.9",
+      "resolved": "https://registry.npmjs.org/debug/-/debug-2.6.9.tgz",
+      "integrity": "sha512-bC7ElrdJaJnPbAP+1EotYvqZsb3ecl5wi6Bfi6BJTUcNowp6cvspg0jXznRTKDjm/E7AdgFBVeAPVMNcKGsHMA==",
+      "license": "MIT",
+      "dependencies": {
+        "ms": "2.0.0"
+      }
+    },
+    "node_modules/compression/node_modules/ms": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/ms/-/ms-2.0.0.tgz",
+      "integrity": "sha512-Tpp60P6IUJDTuOq/5Z8cdskzJujfwqfOTkrwIwj7IRISpnkJnT6SyJ4PCPnGMoFjC9ddhal5KVIYtAt97ix05A==",
+      "license": "MIT"
+    },
+    "node_modules/compression/node_modules/negotiator": {
+      "version": "0.6.4",
+      "resolved": "https://registry.npmjs.org/negotiator/-/negotiator-0.6.4.tgz",
+      "integrity": "sha512-myRT3DiWPHqho5PrJaIRyaMv2kgYf0mUVgBNOYMuCH5Ki1yEiQaf/ZJuQ62nvpc44wL5WDbTX7yGJi1Neevw8w==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 0.6"
+      }
+    },
     "node_modules/content-disposition": {
       "version": "0.5.4",
       "resolved": "https://registry.npmjs.org/content-disposition/-/content-disposition-0.5.4.tgz",
@@ -2869,6 +2924,15 @@
         "node": ">= 0.8"
       }
     },
+    "node_modules/on-headers": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/on-headers/-/on-headers-1.1.0.tgz",
+      "integrity": "sha512-737ZY3yNnXy37FHkQxPzt4UZ2UWPWiCZWLvFZ4fu5cueciegX0zGPnrlY6bwRg4FdQOe9YU8MkmJwGhoMybl8A==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 0.8"
+      }
+    },
     "node_modules/optionator": {
       "version": "0.9.4",
       "resolved": "https://registry.npmjs.org/optionator/-/optionator-0.9.4.tgz",

package.json

@@ -16,6 +16,7 @@
     "preview": "vite preview"
   },
   "dependencies": {
+    "compression": "^1.8.1",
     "express": "^4.19.2",
     "pixi.js": "^8.19.0",
     "react": "^19.2.6",
@@ -36,4 +37,3 @@
     "vite": "^8.0.12"
   }
 }
-

server.js

@@ -1,4 +1,5 @@
 import express from "express";
+import compression from "compression";
 import { spawn } from "child_process";
 import fs from "fs";
 import path from "path";
@@ -999,8 +1000,25 @@ function createDefaultColorCatalogEntries() {
   });
 }
 
+app.use(compression({ threshold: 1024 }));
 app.use(express.json({ limit: "10mb" }));
-app.use(express.static(path.join(__dirname, "dist")));
+app.use(express.static(path.join(__dirname, "dist"), {
+  etag: true,
+  setHeaders(res, filePath) {
+    const normalizedPath = String(filePath || "").replace(/\\/g, "/");
+    if (normalizedPath.includes("/dist/assets/")) {
+      res.setHeader("Cache-Control", "public, max-age=31536000, immutable");
+      return;
+    }
+    if (/\.(png|svg|jpg|jpeg|webp|gif|ico)$/i.test(normalizedPath)) {
+      res.setHeader("Cache-Control", "public, max-age=604800");
+      return;
+    }
+    if (/\.html$/i.test(normalizedPath)) {
+      res.setHeader("Cache-Control", "no-cache");
+    }
+  },
+}));
 
 function resolveContent(type) {
   const entry = contentMap[type];
@@ -1325,6 +1343,33 @@ function listWorldChunkFiles(worldId) {
     .sort((a, b) => a.localeCompare(b));
 }
 
+function buildWorldChunkOverviewSurfaceRows(chunkPayload, fallbackWidth, fallbackHeight) {
+  const width = Math.max(1, Number(chunkPayload?.width) || Number(fallbackWidth) || DEFAULT_WORLD_CHUNK_SIZE);
+  const height = Math.max(1, Number(chunkPayload?.height) || Number(fallbackHeight) || DEFAULT_WORLD_CHUNK_SIZE);
+  const sortedRoomLayers = Array.isArray(chunkPayload?.roomLayers)
+    ? chunkPayload.roomLayers
+      .slice()
+      .sort((left, right) => (Number(left?.layer) || 0) - (Number(right?.layer) || 0))
+    : [];
+  return Array.from({ length: height }, (_entry, rowIndex) => {
+    let row = "";
+    for (let columnIndex = 0; columnIndex < width; columnIndex += 1) {
+      let resolvedSymbol = ".";
+      sortedRoomLayers.forEach((layer) => {
+        const layerNumber = Number(layer?.layer) || 0;
+        const fillChar = layerNumber === 0 ? "." : " ";
+        const sourceRow = Array.isArray(layer?.rows) ? String(layer.rows[rowIndex] || "") : "";
+        const symbol = String(sourceRow.charAt(columnIndex) || fillChar).charAt(0) || fillChar;
+        if (symbol !== "." && symbol !== " ") {
+          resolvedSymbol = symbol;
+        }
+      });
+      row += resolvedSymbol;
+    }
+    return row;
+  });
+}
+
 function countSymbolOccurrencesInRows(rows, targetSymbol) {
   const normalizedTarget = String(targetSymbol || "").charAt(0);
   if (!normalizedTarget) {
@@ -3505,6 +3550,19 @@ app.get("/api/world/:worldId/overview", (req, res) => {
     const chunks = chunkCoords
       .map((coord) => readWorldChunkPayload(worldId, coord.chunkX, coord.chunkY, { createIfMissing: false }))
       .filter(Boolean);
+    const overviewChunks = chunks.map((chunk) => {
+      const width = Math.max(1, Number(chunk.width) || Number(worldDefinition.chunkWidth) || DEFAULT_WORLD_CHUNK_SIZE);
+      const height = Math.max(1, Number(chunk.height) || Number(worldDefinition.chunkHeight) || DEFAULT_WORLD_CHUNK_SIZE);
+      return {
+        chunkX: Math.floor(Number(chunk.chunkX) || 0),
+        chunkY: Math.floor(Number(chunk.chunkY) || 0),
+        width,
+        height,
+        backgroundTileId: String(chunk.backgroundTileId || "").trim(),
+        surfaceRows: buildWorldChunkOverviewSurfaceRows(chunk, width, height),
+        instanceCount: Array.isArray(chunk.instances) ? chunk.instances.length : 0,
+      };
+    });
     const chunkWidth = Math.max(1, Number(worldDefinition.chunkWidth) || DEFAULT_WORLD_CHUNK_SIZE);
     const chunkHeight = Math.max(1, Number(worldDefinition.chunkHeight) || DEFAULT_WORLD_CHUNK_SIZE);
     const minChunkX = chunks.length > 0 ? Math.min(...chunks.map((chunk) => Math.floor(Number(chunk.chunkX) || 0))) : 0;
@@ -3524,8 +3582,8 @@ app.get("/api/world/:worldId/overview", (req, res) => {
         maxTileX: ((maxChunkX + 1) * chunkWidth) - 1,
         maxTileY: ((maxChunkY + 1) * chunkHeight) - 1,
       },
-      chunkCount: chunks.length,
+      chunkCount: overviewChunks.length,
-      chunks,
+      chunks: overviewChunks,
     });
   } catch (err) {
     res.status(500).json({

src/worldshaperStudio/historyController.ts

@@ -1,24 +1,14 @@
-/* eslint-disable @typescript-eslint/ban-ts-comment, no-empty */
+/* eslint-disable @typescript-eslint/ban-ts-comment */
 // @ts-nocheck
 
 export function createHistoryController(scope) {
   const documentScope = scope.documentScope || scope;
   const renderScope = scope.renderScope || scope;
-  const historyScope = scope.historyScope || scope;
   const uiScope = scope.uiScope || scope;
   const sessionScope = scope.sessionScope || scope;
-  const MAX_HISTORY_ENTRIES = 40;
+  const MAX_HISTORY_ENTRIES = 2;
-  const MAX_PERSISTED_HISTORY_CHARS = 1_500_000;
-  const OPERATION_CHECKPOINT_INTERVAL = 12;
   let pendingPersistTimer = 0;
 
-  function cloneValue(value) {
-    if (typeof structuredClone === "function") {
-      return structuredClone(value);
-    }
-    return value == null ? value : JSON.parse(JSON.stringify(value));
-  }
-
   function clearPendingPersistTimer() {
     if (!pendingPersistTimer) {
       return;
@@ -29,102 +19,26 @@ export function createHistoryController(scope) {
 
   function persistHistoryState() {
     clearPendingPersistTimer();
-    try {
-      const savedIndex = Math.max(0, Math.min(
-        scope.historyEntries.findIndex((entry) => Number(entry?.id) === Number(historyScope.lastSavedHistoryId)),
-        scope.historyEntries.length - 1,
-      ));
-      const savedState = scope.historyEntries.length > 0
-        ? captureHistoryStateAtIndex(savedIndex >= 0 ? savedIndex : scope.historyIndex)
-        : captureState();
-      const payload = {
-        mapId: String(documentScope.mapId || scope.mapId || ""),
-        savedStateSignature: getStateSignature(savedState),
-        historyEntries: historyScope.historyEntries,
-        historyIndex: historyScope.historyIndex,
-        historySelectionIndex: historyScope.historySelectionIndex,
-        nextHistoryId: historyScope.nextHistoryId,
-        lastSavedHistoryId: historyScope.lastSavedHistoryId,
-      };
-      const serialized = JSON.stringify(payload);
-      if (serialized.length > MAX_PERSISTED_HISTORY_CHARS) {
-      window.localStorage.removeItem(historyScope.historyStorageKey);
-        return false;
-      }
-      window.localStorage.setItem(historyScope.historyStorageKey, serialized);
     return true;
-    } catch {}
-    return false;
   }
 
   function schedulePersistHistoryState() {
     clearPendingPersistTimer();
-    pendingPersistTimer = window.setTimeout(() => {
-      pendingPersistTimer = 0;
-      persistHistoryState();
-    }, 120);
     return true;
   }
 
   function restoreHistoryState() {
-    try {
-      const raw = window.localStorage.getItem(historyScope.historyStorageKey);
-      if (!raw) {
     return null;
   }
-      const parsed = JSON.parse(raw);
-      if (!parsed || typeof parsed !== "object") {
-        return null;
-      }
-      return parsed;
-    } catch {
-      return null;
-    }
-  }
 
-  function applyHistorySnapshot(snapshot) {
+  function applyHistorySnapshot() {
-    if (!snapshot || typeof snapshot !== "object") {
     return false;
   }
-    const snapshotMapId = String(snapshot.mapId || "").trim();
-    const currentMapId = String(documentScope.mapId || scope.mapId || "").trim();
-    if (snapshotMapId && currentMapId && snapshotMapId !== currentMapId) {
-      return false;
-    }
-    const entries = Array.isArray(snapshot.historyEntries) ? snapshot.historyEntries : null;
-    if (!entries || entries.length === 0) {
-      return false;
-    }
-    const savedId = Number(snapshot.lastSavedHistoryId) || 0;
-    const currentId = Number(snapshot.historyEntries?.[Number(snapshot.historyIndex) || 0]?.id) || 0;
-    if (!savedId || !currentId || savedId !== currentId) {
-      return false;
-    }
-    const savedStateSignature = String(snapshot.savedStateSignature || "").trim();
-    if (savedStateSignature) {
-      const currentLoadedSignature = getStateSignature(captureState());
-      if (savedStateSignature !== currentLoadedSignature) {
-        return false;
-      }
-    }
-    historyScope.historyEntries = entries;
-    historyScope.historyIndex = Math.max(0, Math.min(Number(snapshot.historyIndex) || 0, historyScope.historyEntries.length - 1));
-    historyScope.historySelectionIndex = Math.max(0, Math.min(Number(snapshot.historySelectionIndex) || historyScope.historyIndex, historyScope.historyEntries.length - 1));
-    historyScope.nextHistoryId = Math.max(1, Number(snapshot.nextHistoryId) || (historyScope.historyEntries[historyScope.historyEntries.length - 1]?.seq || 0) + 1);
-    historyScope.lastSavedHistoryId = Math.max(1, Number(snapshot.lastSavedHistoryId) || historyScope.historyEntries[historyScope.historyIndex]?.id || 1);
-    if (!restoreToHistoryIndex(historyScope.historyIndex)) {
-      const currentState = historyScope.historyEntries[historyScope.historyIndex] && historyScope.historyEntries[historyScope.historyIndex].state ? historyScope.historyEntries[historyScope.historyIndex].state : null;
-      if (currentState) {
-        applyState(currentState);
-      }
-    }
-    return true;
-  }
 
   function captureState() {
     return {
-      width: Number(documentScope.width) || 1,
+      width: Math.max(1, Number(documentScope.width) || 1),
-      height: Number(documentScope.height) || 1,
+      height: Math.max(1, Number(documentScope.height) || 1),
       mapName: String(documentScope.mapName || scope.mapId || ""),
       backgroundColor: documentScope.normalizeMapBackgroundColor(documentScope.backgroundColor),
       backgroundTileId: String(documentScope.backgroundTileId || "").trim(),
@@ -142,6 +56,35 @@ export function createHistoryController(scope) {
     };
   }
 
+  function cloneHistoryState(state) {
+    if (!state || typeof state !== "object") {
+      return captureState();
+    }
+    return {
+      width: Math.max(1, Number(state.width) || 1),
+      height: Math.max(1, Number(state.height) || 1),
+      mapName: String(state.mapName || scope.mapId || ""),
+      backgroundColor: documentScope.normalizeMapBackgroundColor(state.backgroundColor),
+      backgroundTileId: documentScope.normalizeBackgroundTileId(state.backgroundTileId),
+      heightBlurStep: Math.max(0, Math.min(1, Number(state.heightBlurStep ?? state.heightDetailStep) || 0.1)),
+      layers: documentScope.cloneLayers(Array.isArray(state.layers) ? state.layers : []),
+      heightLayers: documentScope.cloneHeightLayers(Array.isArray(state.heightLayers) ? state.heightLayers : []),
+      npcs: documentScope.cloneNpcOverlays(Array.isArray(state.npcs) ? state.npcs : []),
+      worldChunkBackgrounds: state && state.worldChunkBackgrounds && typeof state.worldChunkBackgrounds === "object" && !Array.isArray(state.worldChunkBackgrounds)
+        ? { ...state.worldChunkBackgrounds }
+        : {},
+      worldBookmarks: typeof scope.applyWorldBookmarkState === "function" && Array.isArray(state?.worldBookmarks)
+        ? state.worldBookmarks.map((entry) => ({
+          id: String(entry?.id || "").trim(),
+          label: String(entry?.label || entry?.id || "").trim(),
+          x: Math.floor(Number(entry?.x) || 0),
+          y: Math.floor(Number(entry?.y) || 0),
+        }))
+        : [],
+      editorUi: documentScope.cloneEditorUiState(state.editorUi || {}),
+    };
+  }
+
   function refreshUiAfterHistoryMutation() {
     documentScope.ensureBaseLayer();
     sessionScope.activeLayer = documentScope.roomLayers.some((layer) => layer.layer === sessionScope.activeLayer) ? sessionScope.activeLayer : 0;
@@ -185,9 +128,9 @@ export function createHistoryController(scope) {
     documentScope.backgroundColor = documentScope.normalizeMapBackgroundColor(state?.backgroundColor || documentScope.backgroundColor);
     documentScope.backgroundTileId = documentScope.normalizeBackgroundTileId(state?.backgroundTileId);
     documentScope.heightBlurStep = Math.max(0, Math.min(1, Number(state?.heightBlurStep ?? state?.heightDetailStep) || documentScope.heightBlurStep || documentScope.heightDetailStep || 0.1));
-    documentScope.roomLayers = documentScope.cloneLayers(Array.isArray(state.layers) ? state.layers : []);
+    documentScope.roomLayers = documentScope.cloneLayers(Array.isArray(state?.layers) ? state.layers : []);
-    documentScope.heightLayers = documentScope.cloneHeightLayers(Array.isArray(state.heightLayers) ? state.heightLayers : []);
+    documentScope.heightLayers = documentScope.cloneHeightLayers(Array.isArray(state?.heightLayers) ? state.heightLayers : []);
-    const nextNpcs = documentScope.cloneNpcOverlays(Array.isArray(state.npcs) ? state.npcs : []);
+    const nextNpcs = documentScope.cloneNpcOverlays(Array.isArray(state?.npcs) ? state.npcs : []);
     sessionScope.editorUiState = state && state.editorUi ? documentScope.cloneEditorUiState(state.editorUi) : { panelLayouts: {} };
     if (!documentScope.getHeightLayerById(sessionScope.activeHeightLayerId)) {
       sessionScope.activeHeightLayerId = String(documentScope.heightLayers[0]?.id || "").trim();
@@ -202,7 +145,7 @@ export function createHistoryController(scope) {
       scope.applyWorldChunkBackgroundState(state?.worldChunkBackgrounds || {});
     }
     if (typeof scope.applyWorldBookmarkState === "function" && scope.isWorldModeActive?.()) {
-      scope.applyWorldBookmarkState(state?.worldBookmarks || []);
+      scope.applyWorldBookmarkState(Array.isArray(state?.worldBookmarks) ? state.worldBookmarks : []);
     }
     if (typeof scope.rebuildVisibleWorldChunksFromDocument === "function" && typeof scope.isWorldModeActive === "function" && scope.isWorldModeActive()) {
       scope.rebuildVisibleWorldChunksFromDocument();
@@ -212,388 +155,25 @@ export function createHistoryController(scope) {
     }
   }
 
-  function ensureLayerForOperation(layerNumber) {
-    const normalizedLayer = Number(layerNumber) || 0;
-    let layerEntry = scope.roomLayers.find((layer) => Number(layer.layer) === normalizedLayer) || null;
-    if (layerEntry) {
-      return layerEntry;
-    }
-    layerEntry = {
-      layer: normalizedLayer,
-      name: undefined,
-      zIndex: 0,
-      rows: scope.normalizeRows([], normalizedLayer === 0 ? "." : " "),
-      instanceIds: [],
-    };
-    scope.roomLayers.push(layerEntry);
-    scope.roomLayers = scope.roomLayers
-      .slice()
-      .sort((left, right) => Number(left.layer) - Number(right.layer));
-    return scope.roomLayers.find((layer) => Number(layer.layer) === normalizedLayer) || layerEntry;
-  }
-
-  function setStoredTileCharAt(layerNumber, tileX, tileY, nextStoredChar) {
-    if (tileX < 0 || tileX >= scope.width || tileY < 0 || tileY >= scope.height) {
-      return false;
-    }
-    const normalizedLayer = Number(layerNumber) || 0;
-    const layerEntry = ensureLayerForOperation(normalizedLayer);
-    const fillChar = normalizedLayer === 0 ? "." : " ";
-    const rows = scope.normalizeRows(layerEntry.rows, fillChar);
-    const row = rows[tileY] || fillChar.repeat(scope.width);
-    const safeChar = String(nextStoredChar || fillChar).charAt(0) || fillChar;
-    if ((row.charAt(tileX) || fillChar) === safeChar) {
-      return false;
-    }
-    rows[tileY] = row.slice(0, tileX) + safeChar + row.slice(tileX + 1);
-    layerEntry.rows = rows;
-    if (typeof scope.syncWorldChunkCellFromLocalTile === "function" && typeof scope.isWorldModeActive === "function" && scope.isWorldModeActive()) {
-      scope.syncWorldChunkCellFromLocalTile(normalizedLayer, tileX, tileY, safeChar);
-    }
-    return true;
-  }
-
-  function resolveTileOperationCellCoord(cell) {
-    if (typeof scope.isWorldModeActive === "function" && scope.isWorldModeActive()) {
-      const worldX = Number(cell?.worldX);
-      const worldY = Number(cell?.worldY);
-      if (Number.isFinite(worldX) && Number.isFinite(worldY)) {
-        return {
-          x: Math.floor(worldX - (Number(scope.worldTileOffsetX) || 0)),
-          y: Math.floor(worldY - (Number(scope.worldTileOffsetY) || 0)),
-        };
-      }
-    }
-    return {
-      x: Math.floor(Number(cell?.x) || 0),
-      y: Math.floor(Number(cell?.y) || 0),
-    };
-  }
-
-  function applyTileCellsOperation(operation, direction) {
-    const isRedo = direction !== "undo";
-    const nextBackgroundTileId = isRedo
-      ? operation.afterBackgroundTileId
-      : operation.beforeBackgroundTileId;
-    if (nextBackgroundTileId !== undefined) {
-      scope.backgroundTileId = scope.normalizeBackgroundTileId(nextBackgroundTileId);
-    }
-    const cells = Array.isArray(operation.cells) ? operation.cells : [];
-    cells.forEach((cell) => {
-      const resolvedCoord = resolveTileOperationCellCoord(cell, scope.width, scope.height);
-      const nextStoredChar = isRedo ? cell.afterStoredChar : cell.beforeStoredChar;
-      setStoredTileCharAt(cell.layer, resolvedCoord.x, resolvedCoord.y, nextStoredChar);
-    });
-    if (nextBackgroundTileId !== undefined && typeof scope.rebuildVisibleWorldChunksFromDocument === "function" && typeof scope.isWorldModeActive === "function" && scope.isWorldModeActive()) {
-      scope.rebuildVisibleWorldChunksFromDocument();
-    }
-    scope.invalidateTileSurface();
-  }
-
-  function buildNpcTargetEntries(operation, direction) {
-    const useAfter = direction !== "undo";
-    const rawEntries = Array.isArray(operation.entries) ? operation.entries : [];
-    return rawEntries
-      .map((entry) => {
-        const snapshot = useAfter ? entry.after : entry.before;
-        const targetIndex = useAfter ? entry.afterIndex : entry.beforeIndex;
-        if (!snapshot || typeof snapshot !== "object") {
-          return null;
-        }
-        const cloned = scope.cloneNpcOverlays([cloneValue(snapshot)])[0];
-        if (!cloned) {
-          return null;
-        }
-        scope.syncNpcOverlayFromRecord(cloned);
-        return {
-          npc: cloned,
-          index: Math.max(0, Number(targetIndex) || 0),
-        };
-      })
-      .filter((entry) => entry !== null)
-      .sort((left, right) => left.index - right.index);
-  }
-
-  function applyNpcEntriesOperation(operation, direction) {
-    const rawEntries = Array.isArray(operation.entries) ? operation.entries : [];
-    const touchedPositions = [];
-    rawEntries.forEach((entry) => {
-      const beforePos = entry?.before && typeof entry.before === "object" ? entry.before : null;
-      const afterPos = entry?.after && typeof entry.after === "object" ? entry.after : null;
-      if (beforePos) {
-        const x = Math.floor(Number(beforePos.x));
-        const y = Math.floor(Number(beforePos.y));
-        if (Number.isFinite(x) && Number.isFinite(y) && x >= 0 && y >= 0) {
-          touchedPositions.push({ x, y });
-        }
-      }
-      if (afterPos) {
-        const x = Math.floor(Number(afterPos.x));
-        const y = Math.floor(Number(afterPos.y));
-        if (Number.isFinite(x) && Number.isFinite(y) && x >= 0 && y >= 0) {
-          touchedPositions.push({ x, y });
-        }
-      }
-    });
-    const affectedIds = new Set(
-      rawEntries.flatMap((entry) => {
-        const ids = [];
-        const beforeId = String(entry?.before?.id || "").trim();
-        const afterId = String(entry?.after?.id || "").trim();
-        if (beforeId) {
-          ids.push(beforeId);
-        }
-        if (afterId) {
-          ids.push(afterId);
-        }
-        return ids;
-      }),
-    );
-    if (affectedIds.size === 0) {
-      return;
-    }
-    const remainingNpcs = scope.npcOverlays.filter((npc) => !affectedIds.has(String(npc.id || "").trim()));
-    scope.npcOverlays.length = 0;
-    remainingNpcs.forEach((npc) => scope.npcOverlays.push(npc));
-    affectedIds.forEach((npcId) => {
-      delete scope.npcImages[npcId];
-    });
-    const targetEntries = buildNpcTargetEntries(operation, direction);
-    targetEntries.forEach((entry) => {
-      const nextIndex = Math.max(0, Math.min(scope.npcOverlays.length, entry.index));
-      scope.ensureNpcImageLoaded(entry.npc);
-      scope.npcOverlays.splice(nextIndex, 0, entry.npc);
-    });
-    if (typeof scope.rebuildWorldChunksForLocalBounds === "function" && typeof scope.isWorldModeActive === "function" && scope.isWorldModeActive() && touchedPositions.length > 0) {
-      const xs = touchedPositions.map((entry) => entry.x);
-      const ys = touchedPositions.map((entry) => entry.y);
-      scope.rebuildWorldChunksForLocalBounds({
-        minX: Math.min(...xs),
-        minY: Math.min(...ys),
-        maxX: Math.max(...xs),
-        maxY: Math.max(...ys),
-      });
-    }
-  }
-
-  function applyOperation(operation, direction, options) {
-    const config = options && typeof options === "object" ? options : {};
-    if (!operation || typeof operation !== "object") {
-      return false;
-    }
-    if (operation.type === "tile_cells") {
-      applyTileCellsOperation(operation, direction);
-    } else if (operation.type === "npc_entries") {
-      applyNpcEntriesOperation(operation, direction);
-    } else {
-      return false;
-    }
-    if (!config.deferRefresh) {
-      refreshUiAfterHistoryMutation();
-    }
-    return true;
-  }
-
-  function cloneHistoryState(state) {
-    if (!state || typeof state !== "object") {
-      return captureState();
-    }
-    return {
-      width: Math.max(1, Number(state.width) || 1),
-      height: Math.max(1, Number(state.height) || 1),
-      mapName: String(state.mapName || scope.mapId || ""),
-      backgroundColor: documentScope.normalizeMapBackgroundColor(state.backgroundColor),
-      backgroundTileId: documentScope.normalizeBackgroundTileId(state.backgroundTileId),
-      heightBlurStep: Math.max(0, Math.min(1, Number(state.heightBlurStep ?? state.heightDetailStep) || 0.1)),
-      layers: documentScope.cloneLayers(Array.isArray(state.layers) ? state.layers : []),
-      heightLayers: documentScope.cloneHeightLayers(Array.isArray(state.heightLayers) ? state.heightLayers : []),
-      npcs: documentScope.cloneNpcOverlays(Array.isArray(state.npcs) ? state.npcs : []),
-      editorUi: documentScope.cloneEditorUiState(state.editorUi || {}),
-    };
-  }
-
-  function ensureLayerForStateOperation(state, layerNumber) {
-    const normalizedLayer = Number(layerNumber) || 0;
-    let layerEntry = state.layers.find((layer) => Number(layer.layer) === normalizedLayer) || null;
-    if (layerEntry) {
-      return layerEntry;
-    }
-    layerEntry = {
-      layer: normalizedLayer,
-      name: undefined,
-      zIndex: 0,
-      rows: scope.normalizeRows([], normalizedLayer === 0 ? "." : " "),
-      instanceIds: [],
-    };
-    state.layers.push(layerEntry);
-    state.layers = state.layers
-      .slice()
-      .sort((left, right) => Number(left.layer) - Number(right.layer));
-    return state.layers.find((layer) => Number(layer.layer) === normalizedLayer) || layerEntry;
-  }
-
-  function setStoredTileCharAtInState(state, layerNumber, tileX, tileY, nextStoredChar) {
-    if (tileX < 0 || tileX >= state.width || tileY < 0 || tileY >= state.height) {
-      return false;
-    }
-    const normalizedLayer = Number(layerNumber) || 0;
-    const layerEntry = ensureLayerForStateOperation(state, normalizedLayer);
-    const fillChar = normalizedLayer === 0 ? "." : " ";
-    const rows = scope.normalizeRows(layerEntry.rows, fillChar);
-    const row = rows[tileY] || fillChar.repeat(state.width);
-    const safeChar = String(nextStoredChar || fillChar).charAt(0) || fillChar;
-    if ((row.charAt(tileX) || fillChar) === safeChar) {
-      return false;
-    }
-    rows[tileY] = row.slice(0, tileX) + safeChar + row.slice(tileX + 1);
-    layerEntry.rows = rows;
-    return true;
-  }
-
-  function applyTileCellsOperationToState(state, operation, direction) {
-    const nextState = cloneHistoryState(state);
-    const isRedo = direction !== "undo";
-    const nextBackgroundTileId = isRedo
-      ? operation.afterBackgroundTileId
-      : operation.beforeBackgroundTileId;
-    if (nextBackgroundTileId !== undefined) {
-      nextState.backgroundTileId = documentScope.normalizeBackgroundTileId(nextBackgroundTileId);
-    }
-    const cells = Array.isArray(operation.cells) ? operation.cells : [];
-    cells.forEach((cell) => {
-      const resolvedCoord = resolveTileOperationCellCoord(cell, nextState.width, nextState.height);
-      const nextStoredChar = isRedo ? cell.afterStoredChar : cell.beforeStoredChar;
-      setStoredTileCharAtInState(nextState, cell.layer, resolvedCoord.x, resolvedCoord.y, nextStoredChar);
-    });
-    return nextState;
-  }
-
-  function applyNpcEntriesOperationToState(state, operation, direction) {
-    const nextState = cloneHistoryState(state);
-    const rawEntries = Array.isArray(operation.entries) ? operation.entries : [];
-    const affectedIds = new Set(
-      rawEntries.flatMap((entry) => {
-        const ids = [];
-        const beforeId = String(entry?.before?.id || "").trim();
-        const afterId = String(entry?.after?.id || "").trim();
-        if (beforeId) {
-          ids.push(beforeId);
-        }
-        if (afterId) {
-          ids.push(afterId);
-        }
-        return ids;
-      }),
-    );
-    if (affectedIds.size === 0) {
-      return nextState;
-    }
-    const useAfter = direction !== "undo";
-    const remainingNpcs = nextState.npcs.filter((npc) => !affectedIds.has(String(npc.id || "").trim()));
-    const targetEntries = rawEntries
-      .map((entry) => {
-        const snapshot = useAfter ? entry.after : entry.before;
-        const targetIndex = useAfter ? entry.afterIndex : entry.beforeIndex;
-        if (!snapshot || typeof snapshot !== "object") {
-          return null;
-        }
-        const cloned = documentScope.cloneNpcOverlays([cloneValue(snapshot)])[0];
-        if (!cloned) {
-          return null;
-        }
-        documentScope.syncNpcOverlayFromRecord(cloned);
-        return {
-          npc: cloned,
-          index: Math.max(0, Number(targetIndex) || 0),
-        };
-      })
-      .filter((entry) => entry !== null)
-      .sort((left, right) => left.index - right.index);
-    nextState.npcs = remainingNpcs;
-    targetEntries.forEach((entry) => {
-      const nextIndex = Math.max(0, Math.min(nextState.npcs.length, entry.index));
-      nextState.npcs.splice(nextIndex, 0, entry.npc);
-    });
-    return nextState;
-  }
-
-  function captureHistoryStateAtIndex(targetIndex) {
-    const normalizedTargetIndex = Math.max(0, Math.min(Number(targetIndex) || 0, scope.historyEntries.length - 1));
-    const targetEntry = scope.historyEntries[normalizedTargetIndex] || null;
-    if (!targetEntry) {
-      return captureState();
-    }
-    if (targetEntry.state) {
-      return cloneHistoryState(targetEntry.state);
-    }
-    const snapshotIndex = findNearestSnapshotIndex(normalizedTargetIndex);
-    if (snapshotIndex < 0) {
-      return captureState();
-    }
-    let nextState = cloneHistoryState(scope.historyEntries[snapshotIndex].state);
-    for (let index = snapshotIndex + 1; index <= normalizedTargetIndex; index += 1) {
-      const entry = scope.historyEntries[index];
-      if (!entry) {
-        continue;
-      }
-      if (entry.state) {
-        nextState = cloneHistoryState(entry.state);
-        continue;
-      }
-      if (!entry.operation || typeof entry.operation !== "object") {
-        continue;
-      }
-      if (entry.operation.type === "tile_cells") {
-        nextState = applyTileCellsOperationToState(nextState, entry.operation, "redo");
-      } else if (entry.operation.type === "npc_entries") {
-        nextState = applyNpcEntriesOperationToState(nextState, entry.operation, "redo");
-      }
-    }
-    return nextState;
-  }
-
-  function findNearestSnapshotIndex(targetIndex) {
-    for (let index = Math.max(0, Number(targetIndex) || 0); index >= 0; index -= 1) {
-      if (scope.historyEntries[index] && scope.historyEntries[index].state) {
-        return index;
-      }
-    }
-    return -1;
-  }
-
   function restoreToHistoryIndex(targetIndex) {
     const normalizedTargetIndex = Math.max(0, Math.min(Number(targetIndex) || 0, scope.historyEntries.length - 1));
-    const snapshotIndex = findNearestSnapshotIndex(normalizedTargetIndex);
+    const targetEntry = scope.historyEntries[normalizedTargetIndex] || null;
-    if (snapshotIndex < 0) {
+    if (!targetEntry?.state) {
       return false;
     }
-    applyState(scope.historyEntries[snapshotIndex].state, { deferRefresh: true });
+    applyState(targetEntry.state);
-    for (let index = snapshotIndex + 1; index <= normalizedTargetIndex; index += 1) {
-      const entry = scope.historyEntries[index];
-      if (!entry) {
-        continue;
-      }
-      if (entry.state) {
-        applyState(entry.state, { deferRefresh: true });
-        continue;
-      }
-      if (entry.operation) {
-        applyOperation(entry.operation, "redo", { deferRefresh: true });
-      }
-    }
-    refreshUiAfterHistoryMutation();
     return true;
   }
 
   function getStateSignature(state) {
-    const layerSig = scope.cloneLayers(state.layers)
+    const layerSig = scope.cloneLayers(Array.isArray(state?.layers) ? state.layers : [])
-      .sort((a, b) => a.layer - b.layer)
+      .sort((a, b) => Number(a.layer) - Number(b.layer))
       .map((layer) => ({
-        layer: layer.layer,
+        layer: Number(layer.layer) || 0,
         name: typeof layer.name === "string" ? layer.name : "",
-        rows: scope.normalizeRows(layer.rows, layer.layer === 0 ? "." : " "),
+        rows: scope.normalizeRows(layer.rows, Number(layer.layer) === 0 ? "." : " "),
       }));
-    const heightLayerSig = scope.cloneHeightLayers(state.heightLayers)
+    const heightLayerSig = scope.cloneHeightLayers(Array.isArray(state?.heightLayers) ? state.heightLayers : [])
       .sort((a, b) => String(a.id || "").localeCompare(String(b.id || "")))
       .map((entry) => ({
         id: String(entry.id || ""),
@@ -603,30 +183,38 @@ export function createHistoryController(scope) {
         y: Number(entry.y) || 0,
         rows: Array.isArray(entry.rows) ? entry.rows.map((row) => String(row || "")) : [],
       }));
-    const npcSig = scope.cloneNpcOverlays(state.npcs)
+    const npcSig = scope.cloneNpcOverlays(Array.isArray(state?.npcs) ? state.npcs : [])
-      .sort((a, b) => a.id.localeCompare(b.id))
+      .sort((a, b) => String(a.id || "").localeCompare(String(b.id || "")))
       .map((entry) => ({
-        id: entry.id,
+        id: String(entry.id || ""),
         layer: Number(entry.layer) || 0,
-        name: entry.name,
+        name: String(entry.name || ""),
-        spriteId: entry.spriteId,
+        spriteId: String(entry.spriteId || ""),
-        x: entry.x,
+        x: Number(entry.x) || 0,
-        y: entry.y,
+        y: Number(entry.y) || 0,
       }));
     return JSON.stringify({
-      width: Number(state.width) || 1,
+      width: Math.max(1, Number(state?.width) || 1),
-      height: Number(state.height) || 1,
+      height: Math.max(1, Number(state?.height) || 1),
-      mapName: String(state.mapName || ""),
+      mapName: String(state?.mapName || ""),
-      backgroundColor: scope.normalizeMapBackgroundColor(state.backgroundColor),
+      backgroundColor: scope.normalizeMapBackgroundColor(state?.backgroundColor),
-      backgroundTileId: scope.normalizeBackgroundTileId(state.backgroundTileId),
+      backgroundTileId: scope.normalizeBackgroundTileId(state?.backgroundTileId),
-      heightBlurStep: Math.max(0, Math.min(1, Number(state.heightBlurStep ?? state.heightDetailStep) || 0.1)),
+      heightBlurStep: Math.max(0, Math.min(1, Number(state?.heightBlurStep ?? state?.heightDetailStep) || 0.1)),
       layerSig,
       heightLayerSig,
       npcSig,
       worldChunkBackgrounds: state && state.worldChunkBackgrounds && typeof state.worldChunkBackgrounds === "object" && !Array.isArray(state.worldChunkBackgrounds)
         ? state.worldChunkBackgrounds
         : {},
-      editorUi: scope.cloneEditorUiState(state.editorUi || {}),
+      worldBookmarks: Array.isArray(state?.worldBookmarks)
+        ? state.worldBookmarks.map((entry) => ({
+          id: String(entry?.id || ""),
+          label: String(entry?.label || ""),
+          x: Number(entry?.x) || 0,
+          y: Number(entry?.y) || 0,
+        }))
+        : [],
+      editorUi: scope.cloneEditorUiState(state?.editorUi || {}),
     });
   }
 
@@ -642,50 +230,29 @@ export function createHistoryController(scope) {
   }
 
   function renderHistoryPreview() {
-    const selectedEntry = scope.historyEntries[scope.historySelectionIndex] || null;
+    if (!scope.historyPreviewEl) {
-    if (!selectedEntry) {
+      return;
-      scope.historyPreviewEl.innerHTML = '<h4>Change Preview</h4><div class="history-preview-empty">Select a history entry to inspect it.</div>';
+    }
+    const selectedEntry = scope.historyEntries[scope.historySelectionIndex] || null;
+    if (!selectedEntry) {
+      scope.historyPreviewEl.innerHTML = '<h4>Undo / Redo</h4><div class="history-preview-empty">Single-step history is empty.</div>';
       return;
     }
-
     const details = Array.isArray(selectedEntry.details) ? selectedEntry.details : [];
     const detailHtml = details.length > 0
       ? "<ul>" + details.map((detail) => "<li>" + detail + "</li>").join("") + "</ul>"
       : '<div class="history-preview-empty">No additional details recorded.</div>';
-    const currentText = scope.historySelectionIndex === scope.historyIndex ? "Current state" : "Selected step " + selectedEntry.seq;
+    const title = scope.historySelectionIndex === scope.historyIndex ? "Current state" : "Single undo step";
     scope.historyPreviewEl.innerHTML =
-      "<h4>" + currentText + "</h4>" +
+      "<h4>" + title + "</h4>" +
       '<div style="margin-bottom:6px;">' + formatHistoryLabel(selectedEntry) + "</div>" +
       detailHtml +
-      '<button class="mini-btn" id="jumpHistoryBtn" type="button" style="margin-top:8px;">Restore To Selected</button>';
+      '<div class="history-preview-empty" style="margin-top:8px;">Only one undo / redo step is kept in memory.</div>';
-
-    const nextJumpBtn = document.getElementById("jumpHistoryBtn");
-    nextJumpBtn.disabled = scope.isSaving || scope.historySelectionIndex === scope.historyIndex;
-    nextJumpBtn.addEventListener("click", () => {
-      if (scope.historySelectionIndex === scope.historyIndex) {
-        return;
-      }
-      scope.historyIndex = scope.historySelectionIndex;
-      restoreToHistoryIndex(scope.historyIndex);
-      refreshToolbarState();
-      scope.setStatus("Restored to history step " + scope.historyEntries[scope.historyIndex].seq + ".", false);
-    });
   }
 
   function renderHistoryList() {
+    if (scope.historyListEl) {
       scope.historyListEl.innerHTML = "";
-    if (scope.historyCurrentEl) {
-      const currentEntry = scope.historyEntries[scope.historyIndex] || null;
-      scope.historyCurrentEl.innerHTML = currentEntry
-        ? (
-          '<div class="history-current-label">Current State</div>' +
-          '<button type="button" class="history-row current-row">' +
-            "<span>" + String(currentEntry.seq) + ". " + formatHistoryLabel(currentEntry) + "</span>" +
-            '<span class="history-meta">' + new Date(currentEntry.createdAt).toLocaleTimeString() + "</span>" +
-          "</button>"
-        )
-        : '<div class="history-current-label">Current State</div><div class="history-current-empty">No history yet.</div>';
-    }
       scope.historyEntries.forEach((entry, index) => {
         if (index === scope.historyIndex) {
           return;
@@ -708,12 +275,25 @@ export function createHistoryController(scope) {
         scope.historyListEl.appendChild(row);
       });
     }
+    if (scope.historyCurrentEl) {
+      const currentEntry = scope.historyEntries[scope.historyIndex] || null;
+      scope.historyCurrentEl.innerHTML = currentEntry
+        ? (
+          '<div class="history-current-label">Current State</div>' +
+          '<button type="button" class="history-row current-row">' +
+            "<span>" + String(currentEntry.seq) + ". " + formatHistoryLabel(currentEntry) + "</span>" +
+            '<span class="history-meta">' + new Date(currentEntry.createdAt).toLocaleTimeString() + "</span>" +
+          "</button>"
+        )
+        : '<div class="history-current-label">Current State</div><div class="history-current-empty">No history yet.</div>';
+    }
+  }
 
   function refreshToolbarState(preserveCurrentStatus) {
     const canUndo = scope.historyIndex > 0;
     const canRedo = scope.historyIndex < scope.historyEntries.length - 1;
-    const currentHistoryId = scope.historyEntries[scope.historyIndex] ? scope.historyEntries[scope.historyIndex].id : 0;
+    const currentHistoryId = scope.historyEntries[scope.historyIndex] ? Number(scope.historyEntries[scope.historyIndex].id) || 0 : 0;
-    const isDirtyFromSaved = currentHistoryId !== scope.lastSavedHistoryId;
+    const isDirtyFromSaved = currentHistoryId !== (Number(scope.lastSavedHistoryId) || 0);
 
     scope.undoBtn.disabled = scope.isSaving || !canUndo;
     scope.redoBtn.disabled = scope.isSaving || !canRedo;
@@ -725,13 +305,12 @@ export function createHistoryController(scope) {
     if (preserveCurrentStatus) {
       return;
     }
-
     if (scope.isSaving) {
       scope.setStatus("Saving...", false);
     } else if (canRedo) {
-      scope.setStatus("History branch active. New edits will replace future steps.", false);
+      scope.setStatus("Redo is available. A new edit will replace it.", false);
     } else if (isDirtyFromSaved) {
-      scope.setStatus("Unsaved history changes.", false);
+      scope.setStatus("Unsaved changes.", false);
     } else {
       scope.setStatus("All changes saved.", false);
     }
@@ -739,20 +318,10 @@ export function createHistoryController(scope) {
 
   function registerHistory(label, before, after, details, options) {
     const config = options && typeof options === "object" ? options : {};
-    const operation = config.operation ? cloneValue(config.operation) : null;
+    const nextState = cloneHistoryState(config.nextState || captureState());
-    if (operation && operation.type === "tile_cells" && (!Array.isArray(operation.cells) || operation.cells.length === 0)) {
-      return;
-    }
-    if (operation && operation.type === "npc_entries" && (!Array.isArray(operation.entries) || operation.entries.length === 0)) {
-      return;
-    }
-    const shouldStoreOperationOnly = Boolean(operation);
-    const nextState = shouldStoreOperationOnly ? null : (config.nextState || captureState());
     const currentEntry = scope.historyEntries[scope.historyIndex] || null;
-    const currentState = currentEntry && currentEntry.state
+    const currentState = currentEntry?.state ? cloneHistoryState(currentEntry.state) : captureState();
-      ? currentEntry.state
+    if (!config.skipStateCheck && getStateSignature(nextState) === getStateSignature(currentState)) {
-      : captureHistoryStateAtIndex(scope.historyIndex);
-    if (!config.skipStateCheck && nextState && currentState && getStateSignature(nextState) === getStateSignature(currentState)) {
       return;
     }
 
@@ -760,25 +329,6 @@ export function createHistoryController(scope) {
       scope.historyEntries = scope.historyEntries.slice(0, scope.historyIndex + 1);
     }
 
-    let operationEntriesSinceSnapshot = 0;
-    if (shouldStoreOperationOnly) {
-      for (let index = scope.historyEntries.length - 1; index >= 0; index -= 1) {
-        const entry = scope.historyEntries[index];
-        if (!entry) {
-          continue;
-        }
-        if (entry.state) {
-          break;
-        }
-        if (entry.operation) {
-          operationEntriesSinceSnapshot += 1;
-        }
-      }
-    }
-    const checkpointState = shouldStoreOperationOnly && operationEntriesSinceSnapshot + 1 >= OPERATION_CHECKPOINT_INTERVAL
-      ? captureState()
-      : null;
-
     const entry = {
       id: scope.nextHistoryId,
       seq: scope.nextHistoryId,
@@ -787,47 +337,47 @@ export function createHistoryController(scope) {
       before,
       after,
       details: Array.isArray(details) ? details : [],
-      state: nextState || checkpointState,
+      state: nextState,
-      operation,
     };
     scope.nextHistoryId += 1;
-
     scope.historyEntries.push(entry);
+    if (scope.historyEntries.length > MAX_HISTORY_ENTRIES) {
+      scope.historyEntries = scope.historyEntries.slice(scope.historyEntries.length - MAX_HISTORY_ENTRIES);
+    }
     scope.historyIndex = scope.historyEntries.length - 1;
     scope.historySelectionIndex = scope.historyIndex;
-    if (scope.historyEntries.length > MAX_HISTORY_ENTRIES) {
-      const trimmedCount = scope.historyEntries.length - MAX_HISTORY_ENTRIES;
-      scope.historyEntries = scope.historyEntries.slice(trimmedCount);
-      scope.historyIndex = Math.max(0, scope.historyIndex - trimmedCount);
-      scope.historySelectionIndex = Math.max(0, scope.historySelectionIndex - trimmedCount);
-    }
-
     schedulePersistHistoryState();
     refreshToolbarState();
   }
 
   function undo() {
     if (scope.historyIndex <= 0) {
-      return;
+      return false;
     }
     scope.historyIndex -= 1;
     scope.historySelectionIndex = scope.historyIndex;
-    restoreToHistoryIndex(scope.historyIndex);
+    const restored = restoreToHistoryIndex(scope.historyIndex);
     schedulePersistHistoryState();
     refreshToolbarState();
-    scope.setStatus("Undo to step " + scope.historyEntries[scope.historyIndex].seq + ".", false);
+    if (restored) {
+      scope.setStatus("Undid the last change.", false);
+    }
+    return restored;
   }
 
   function redo() {
     if (scope.historyIndex >= scope.historyEntries.length - 1) {
-      return;
+      return false;
     }
     scope.historyIndex += 1;
     scope.historySelectionIndex = scope.historyIndex;
-    restoreToHistoryIndex(scope.historyIndex);
+    const restored = restoreToHistoryIndex(scope.historyIndex);
     schedulePersistHistoryState();
     refreshToolbarState();
-    scope.setStatus("Redo to step " + scope.historyEntries[scope.historyIndex].seq + ".", false);
+    if (restored) {
+      scope.setStatus("Redid the last change.", false);
+    }
+    return restored;
   }
 
   return {
@@ -837,7 +387,7 @@ export function createHistoryController(scope) {
     applyHistorySnapshot,
     captureState,
     applyState,
-    applyOperation,
+    applyOperation: () => false,
     restoreToHistoryIndex,
     getStateSignature,
     formatCellCoord,

src/worldshaperStudio/runtime.ts

@@ -4513,11 +4513,12 @@ export function startWorldshaperStudio(bootstrap: WorldshaperStudioBootstrap, in
       scope.historySelectionIndex = 0;
       scope.lastSavedHistoryId = initialEntry.id;
       scope.nextHistoryId = initialEntry.id + 1;
-
+      try {
-      const restoredHistory = scope.restoreHistoryState();
+        if (currentHistoryStorageKey) {
-      if (!scope.applyHistorySnapshot(restoredHistory)) {
+          window.localStorage.removeItem(currentHistoryStorageKey);
-        scope.persistHistoryState();
         }
+      } catch {}
+      scope.persistHistoryState();
     }
 
     function refreshUiForLoadedMap() {

src/worldshaperStudio/worldOverviewWindowController.ts

@@ -46,7 +46,9 @@ type OverviewChunk = {
   height?: number;
   backgroundTileId?: string;
   roomLayers?: OverviewRoomLayer[];
+  surfaceRows?: string[];
   instances?: unknown[];
+  instanceCount?: number;
 };
 
 type OverviewPayload = {
@@ -860,7 +862,9 @@ export function createWorldOverviewWindowController(scope: WorldOverviewScope) {
   }
 
   function beginPendingChunkAction(type: "move" | "duplicate", chunkRect: ChunkWorldRect, chunkKey: string, chunk?: OverviewChunk | null) {
-    const entityCount = Array.isArray(chunk?.instances) ? chunk.instances.length : 0;
+    const entityCount = Array.isArray(chunk?.instances)
+      ? chunk.instances.length
+      : Math.max(0, Math.floor(Number(chunk?.instanceCount) || 0));
     if (type === "move" && entityCount > 0) {
       const confirmed = window.confirm(
         "Move chunk " + chunkRect.chunkX + "," + chunkRect.chunkY + "?\n\nThis will also move " + entityCount + " placed entit" + (entityCount === 1 ? "y" : "ies") + ".",
@@ -1395,13 +1399,15 @@ export function createWorldOverviewWindowController(scope: WorldOverviewScope) {
     return String(entry?.symbol || ".").charAt(0) || ".";
   }
 
-  function getTopVisibleSymbol(chunk: OverviewChunk | null | undefined, localX: number, localY: number) {
+  function getTopVisibleSymbol(
+    chunk: OverviewChunk | null | undefined,
+    sortedRoomLayers: OverviewRoomLayer[],
+    localX: number,
+    localY: number,
+  ) {
     const backgroundSymbol = getBackgroundSymbol(chunk);
-    const roomLayers = Array.isArray(chunk?.roomLayers)
-      ? chunk.roomLayers.slice().sort((left: OverviewRoomLayer, right: OverviewRoomLayer) => (Number(left?.layer) || 0) - (Number(right?.layer) || 0))
-      : [];
     let resolvedSymbol = backgroundSymbol || "";
-    roomLayers.forEach((layer: OverviewRoomLayer) => {
+    sortedRoomLayers.forEach((layer: OverviewRoomLayer) => {
       const layerNumber = Number(layer?.layer) || 0;
       const fillChar = layerNumber === 0 ? "." : " ";
       const row = Array.isArray(layer?.rows) ? String(layer.rows[localY] || "") : "";
@@ -1433,7 +1439,8 @@ export function createWorldOverviewWindowController(scope: WorldOverviewScope) {
   }
 
   function buildChunkSurfaceSignature(chunk: OverviewChunk | null | undefined) {
-    const roomLayerSig = (Array.isArray(chunk?.roomLayers) ? chunk.roomLayers : [])
+    const surfaceSig = Array.isArray(chunk?.surfaceRows) ? chunk.surfaceRows.join("|") : "";
+    const roomLayerSig = surfaceSig || (Array.isArray(chunk?.roomLayers) ? chunk.roomLayers : [])
       .map((layer: OverviewRoomLayer) => String(Number(layer?.layer) || 0) + ":" + (Array.isArray(layer?.rows) ? layer.rows.join("|") : ""))
       .join("~");
     return [
@@ -1459,10 +1466,18 @@ export function createWorldOverviewWindowController(scope: WorldOverviewScope) {
     canvas.height = chunkHeight;
     const ctx = canvas.getContext("2d");
     if (ctx) {
+      const surfaceRows = Array.isArray(chunk?.surfaceRows) ? chunk.surfaceRows : null;
+      const sortedRoomLayers = Array.isArray(chunk?.roomLayers)
+        ? chunk.roomLayers.slice().sort((left: OverviewRoomLayer, right: OverviewRoomLayer) => (Number(left?.layer) || 0) - (Number(right?.layer) || 0))
+        : [];
       const imageData = ctx.createImageData(chunkWidth, chunkHeight);
       for (let localY = 0; localY < chunkHeight; localY += 1) {
+        const surfaceRow = surfaceRows ? String(surfaceRows[localY] || "") : "";
         for (let localX = 0; localX < chunkWidth; localX += 1) {
-          const color = getSymbolColor(getTopVisibleSymbol(chunk, localX, localY), chunk);
+          const visibleSymbol = surfaceRow
+            ? (String(surfaceRow.charAt(localX) || ".").charAt(0) || ".")
+            : getTopVisibleSymbol(chunk, sortedRoomLayers, localX, localY);
+          const color = getSymbolColor(visibleSymbol, chunk);
           const pixelIndex = (localY * chunkWidth + localX) * 4;
           imageData.data[pixelIndex] = color[0];
           imageData.data[pixelIndex + 1] = color[1];