I found a solution here http://askubuntu.com/questions/107583/remove-duplicate-second-unity-launcher-on-dual-screen. I turned off sticky edges and set the launcher to just one screen. It could be that the setting was changed.
I found a solution here http:// askubuntu. com/questions/ 107583/ remove- duplicate- second- unity-launcher- on-dual- screen. I turned off sticky edges and set the launcher to just one screen. It could be that the setting was changed.