I try again as you ask and they work fine. It's right as you said, just make it a child of another object and it works.
Generally, the only solution is just make it a child of another object to see if it works, if not, go back to DesktopX 3.1 (and now, I am enjoying DesktopX 3.1). Done.
DesktopX 3.5 is full of bugs, all of us hope the future versions would be better.
Thanks again, sViz! I have disturbed you a lot. Good time!