PM Limit

Not sure if this is a just me thing...but I noticed there's only a certain ammount of people I can PM. And at a certain point on the list of people I've messaged, it stops listing that person. Any chance it could be changed so that instead of that the list has no limits?
I ask because there were a few cases before I found this out, I never sent an official friend request to the person and the server got deleted. Thus the RP I was doing with someone over PM was eventually lost.