Thank you, Wizard1956, JcRabbit, and Dewie, for your replies.
If this issue comes from Microsoft and is specific to Windows 7 then I don't see any quick solution to this "feature", if not a "problem", in the near future. It's odd though that I didn't experience any "right side background" issue with the Start Menu Docklet in the old version, as is shown in the attached picture.
I placed the windows task bar on the top of the desktop mainly because at times some system messages were popped up from the hidden task bar which would overlap with the Objectdock icons if the Windows task bar was placed on the bottom. In addition, I had to check the Windows task bar in some occasions, e.g. some system tray icons which couldn't be shown in the Objectdock system tray or stalled processes to be terminated manually. It's more convenient to place the Windows task bar on the top so it won't get blocked by the Objectdock icons.
On the other hand, placing the Windows task bar on the bottom still has the "oriented" issue since the pop-up menu will be shown at the left-most side of the desktop, not immediately adjacent to the Start Menu Docklet. It's not as annoying as when the menu pops up on the top, of course.
I restored the system from my ghost backup last night and things were back to what it used to be. I actually had no problem using the old beta version of Ojectdock plus 2.0. It did what I wanted it to do, with some minor glitches though. Nevertheless, I am pretty satisfied with its functionality. I think I'll stay with the old beta version until some "breakthrough" upgrade comes up.
I want to thank you guys who offered your responses and help. Thanks.
