Hhm, yes... I forgot to remove that dirty workaround. While playing around with IterNext/IterPrevious I experienced the problem that iter.UserData was null, so it crashed. Since there are almost no ArgumentNullExcpetion checks anywhere in Xwt, I added this workaround (if null is passed or the handle is broken, it returns null).

I think this can be reverted. Should it?