Your comments

This still happens to me same as @shottogan

I am using Chronos v.2.4.14 and Unity v2018.3.0f2

NullReferenceException: Object reference not set to an instance of an object
Chronos.ReorderableList.ReorderableListControl.PrepareState (System.Int32 controlID, Chronos.ReorderableList.IReorderableListAdaptor adaptor) (at Assets/Chronos/Source/Dependencies/ReorderableList/Editor/ReorderableListControl.cs:586)
Chronos.ReorderableList.ReorderableListControl.Draw (System.Int32 controlID, Chronos.ReorderableList.IReorderableListAdaptor adaptor, Chronos.ReorderableList.ReorderableListControl+DrawEmpty drawEmpty) (at Assets/Chronos/Source/Dependencies/ReorderableList/Editor/ReorderableListControl.cs:1376)
Chronos.ReorderableList.ReorderableListControl.DrawControlFromState (Chronos.ReorderableList.IReorderableListAdaptor adaptor, Chronos.ReorderableList.ReorderableListControl+DrawEmpty drawEmpty, Chronos.ReorderableList.ReorderableListFlags flags) (at Assets/Chronos/Source/Dependencies/ReorderableList/Editor/ReorderableListControl.cs:184)
Chronos.ReorderableList.ReorderableListGUI.DoListField (UnityEditor.SerializedProperty arrayProperty, System.Single fixedItemHeight, Chronos.ReorderableList.ReorderableListControl+DrawEmpty drawEmpty, Chronos.ReorderableList.ReorderableListFlags flags) (at Assets/Chronos/Source/Dependencies/ReorderableList/Editor/ReorderableListGUI.cs:358)
Chronos.ReorderableList.ReorderableListGUI.ListField (UnityEditor.SerializedProperty arrayProperty, Chronos.ReorderableList.ReorderableListFlags flags) (at Assets/Chronos/Source/Dependencies/ReorderableList/Editor/ReorderableListGUI.cs:396)
Chronos.CustomRecorderEditor.OnInspectorGUI () (at Assets/Chronos/Source/Editor/CustomRecorderEditor.cs:24)
UnityEditor.InspectorWindow.DoOnInspectorGUI (System.Boolean rebuildOptimizedGUIBlock, UnityEditor.Editor editor, System.Boolean wasVisible, UnityEngine.Rect& contentRect) (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:1625)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)