why is this person so high up on my facebook chat list?

[Aureustron]

so i used to like this girl so i would "creep" her facebook profile like her photos and stuff but then i stopped and i havent chatted to her on fb for more than 6 months and i dont go on her profile too often, very occasionally. i go on other people's page WAY more than i go on hers now but she is still so high up on my chat list! like when u do the view page source, she has been consistently high up while other people changed in order. like my best friend was number 1 but he moved down a few spots because we've apart for a while and now my number one is a girl i recently liked and i go on her profile and chat her frequently. i just dont understand why other people's order are changing but not the girl i used to like!?
i havent messaged her in 6 months and i havent been on her profile at all

[Leslie]

If you messaged her alot or go to their profile multiple times then that's probably why.