The King of the Netherlands held the Grand Duchy of Luxembourg in personal union, keeping it past Belgium independence. In 1890 Luxembourg separated from the Netherlands due to salic law. In 1907, the Grand Duke of Luxembourg changed the law to enable females to inherit the duchy.
This was slick. Supposing the Netherlands had bothered to change the law before 1890 to enable Luxembourg to be inherited by females, or just completely incorporated the duchy into the Netherlands? If the law was changed later anyway, this would have been feasible
Would this be a triviality or have had major effects? I think this is one of those small things that could wind up having lots of ripple effects.