Update IdLabelConfigEditor.cs

com.unity.perception/Editor/GroundTruth/IdLabelConfigEditor.cs

         protected override IdLabelEntry CreateLabelEntryFromLabelString(SerializedProperty serializedArray,
             string labelToAdd)
         {
-            int maxLabel = Int32.MinValue;
+            var maxLabel = int.MinValue;
-            for (int i = 0; i < serializedArray.arraySize; i++)
+            for (var i = 0; i < serializedArray.arraySize; i++)
+            }
+
+            if (maxLabel == -1)
+            {
+                var startingLabelId =
+                    (StartingLabelId) serializedObject.FindProperty(nameof(IdLabelConfig.startingLabelId)).enumValueIndex;
+                if (startingLabelId == StartingLabelId.One)
+                    maxLabel = 0;
             }
 
             return new IdLabelEntry