safari top sites, missing block?

I have this weird problem with top sites, it actually happened quite a while ago but i havent gotten around to it until now, basically when i open top sites, theres one empty block space, as you can see in the following screenshot. all the blacked out websites work perfectly fine and they can be moved around to all the spaces, but theres always one empty space left. when i change the amount of top sites i want shown to six the empty block disappears, but when i have 12 or 24 top sites shown, its always there. Honestly I have no idea if i caused this or it happened for some other reason. Any ideas? Thanks for your time!