There's an option to select which board to search in, for those who don't know. If you know this already, disregard this post.
By unchecking "Check All," it unchecks all the boards. You can select what boards to search in.
If I sound like a richard, I'm sorry, but it isn't that hard.
Or you can just google "BlockLand slayer" and it will most likely be the first result.