Bug with the crosshair when you have something green in you're hotbar

When you have something like a vine on you're hotbar it changes to that color as shown here: http://i.imgur.com/RfF74zj.png but when you don't have anything green on you're hotbar it gose back to normal http://i.imgur.com/Da21Gri.png I don't know if this is a bug or not