Have you ever found yourself when you do not need an outfit, its everywhere in every shop you go to, but the day you actually want the outfit it disappear from the shops. So you start trying to remember where you saw it, all the shops. Yes that happens to me all the time when it comes to all white parties.
I am sorry I do not know how to resolve this issue all I can say is maybe if you buy the outfit when its most popular, tadaaa issue resolved lol. The only issue is when is that day coming to wear that outfit.