Try load chunk data.

tools/editortool/map/ChunkData.py

@@ -0,0 +1,36 @@
+import json
+
+class ChunkData:
+    def __init__(self):
+        self.current = {}
+        self.original = {}
+        self.filename = None
+
+    def load(self, filename):
+        try:
+            with open(filename, 'r') as f:
+                self.current = json.load(f)
+            self.filename = filename
+            self.original = json.loads(json.dumps(self.current))  # Deep copy
+        except Exception as e:
+            raise RuntimeError(f"Failed to load chunk file: {e}")
+
+    def save(self, filename=None):
+        fname = filename if filename else self.filename
+        if not fname:
+            raise ValueError("No filename specified for saving chunk.")
+        try:
+            with open(fname, 'w') as f:
+                json.dump(self.current, f, indent=2)
+            self.original = json.loads(json.dumps(self.current))  # Deep copy
+            self.filename = fname
+        except Exception as e:
+            raise RuntimeError(f"Failed to save chunk file: {e}")
+
+    def new(self):
+        self.current = {}
+        self.original = {}
+        self.filename = None
+
+    def isDirty(self):
+        return json.dumps(self.current, sort_keys=True) != json.dumps(self.original, sort_keys=True)