I have been playing in snapshot 14w25b on the map "Captive Minecraft" by The Farlanders, and I have been experiencing an odd bug with the crosshair. Instead of it's usual + shape, it appears to be a translucent box of some sort. It changes colors depending on where you aim it, and is somewhat of an eye-sore. Maybe it has to do with the world border that is very close to the player, or possibly the texture pack I am using. I hope you can take a look at this yourself on the map, and see if the same thing happens to you. Thank you for reading! - Frog
This issue has been reported already. It has been linked to the original bugreport.
Please search before reporting any bugs, as it's likely that one exists already.