Have a look here and here.

LFSW Remote seems to have trouble displaying servers with a large amount of people on them. Example picture attached, I guess it says it all. It only happens with plus 42 (or something, couldn't find out the exact number) connections, as soon as it goes under that mark it will show up nicely again.

I have been trying to fix these disappearing button issues, but could only partially solve them so far. See from this post on onwards : http://www.lfsforum.net/showthread.php?p=1693811#post1693811

tbh i think it's a bug in flash related to masked objects