This has probably been going on for about a week or two now. I've tried it in both Firefox and Chrome and can confirm that the issue runs across them both.
I have the same issue. I tried to add Bioshock to my "queue" I have for myself and then bump it to my #1 in the list. When I save it disappears, and my list starts at #2...I also tried adding other games and they disappear when I save... I can continually re-add games but they always disappear.
@quixy: Where are you having trouble? You should be able to just type in an item in the search box at the bottom of the list you're trying to create or edit, and they'll appear when you type them in. Let me know if you're having an issue.