Exception: Index was out of range

[Krzeszny]

I think this mod might've crashed FrooxEngine once:

❌5:51:52 AM.822 (FPS: 75):	Exception running asynchronous task:
System.AggregateException: One or more errors occurred. (Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index'))
 ---> System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index')
   at T System.Collections.Generic.List<T>.get_Item(int index)
   at T Elements.Core.CollectionsExtensions.GetFirst<T>(IList<T> list) in /home/runner/work/FrooxEngine/FrooxEngine/FrooxEngine/Elements.Core/Extensions/CollectionsExtensions.cs:line 127
   at async void ContextMenuBackOption.ContextMenuBackOption.GeneralButtonHandler(User user, IWorldElement summoner, Slot pointer, ContextMenuOptions options)+(?) => { }
   --- End of inner exception stack trace ---

   at string SyncProxy<System.String System.Environment:get_StackTrace()>(?)
   at void Elements.Core.UniLog.Error(string message, bool stackTrace) in /home/runner/work/FrooxEngine/FrooxEngine/FrooxEngine/Elements.Core/UniLog.cs:line 78
   at bool System.Threading.ThreadPoolWorkQueue.Dispatch()
   at void System.Threading.PortableThreadPool+WorkerThread.WorkerThreadStart()
   at void System.Threading.Thread.StartCallback()
ℹ️5:52:20 AM.557 (FPS: 75):	Running refresh on: OwnerId: U-1QKbgAY9OXA, Path: G-Resonite.Favorites.AudioStreamController
ℹ️5:52:20 AM.557 (FPS: 75):	Running refresh on: OwnerId: U-1QKbgAY9OXA, Path: G-Resonite.Favorites.WorldLoadingIndicator
ℹ️5:52:20 AM.557 (FPS: 75):	Running refresh on: OwnerId: U-1QKbgAY9OXA, Path: G-Resonite.Favorites.Camera
ℹ️5:52:20 AM.557 (FPS: 75):	Running refresh on: OwnerId: U-1QKbgAY9OXA, Path: G-Resonite.Favorites.DocumentDisplay
ℹ️5:52:20 AM.557 (FPS: 75):	Running refresh on: OwnerId: U-1QKbgAY9OXA, Path: G-Resonite.Favorites.ColorDialog
ℹ️5:52:20 AM.557 (FPS: 75):	Running refresh on: OwnerId: U-1QKbgAY9OXA, Path: G-Resonite.Favorites.UrlDisplay
ℹ️5:52:20 AM.557 (FPS: 75):	Running refresh on: OwnerId: U-1QKbgAY9OXA, Path: G-Resonite.Favorites.NoticeDisplay
ℹ️5:52:20 AM.557 (FPS: 75):	Running refresh on: OwnerId: U-1QKbgAY9OXA, Path: G-Resonite.Favorites.NamePlate
ℹ️5:52:20 A