Docky Double Image

I using Freya x64. When I add an app to Docky, the app icon appears to get tied with mouse icon, so, no matters I move the mouse, the app follows the mouse icon. This disappears only when I log off or when I lock and unlock the desktop.

Some months ago I installed in Ubuntu 14.04 an app called Docky, and the same behavior did in the past using this scenario. If is needed I can post a photo to better explain whats is going on.

Tks,

Marcelo.