Not sure if its a bug or I have a setting set somewhere, but when I drag an icon from my desktop into a tab dock I get a mirror images of the icons that were in the dock before adding the new icon.

I dragged the Chrome icon from my desktop to the tab dock and the Notepad ++ icon and a shortcut to my windows home server icon mirrored themselves.
Running ObjectDock Plus 2 on Windows 7 64-bit with a ATI Radeon 5970 video card