With jQuery 1.4.1 and UI 1.7.2

After I open a modal dialog from a modal dialog, the original modal dialog is blocked out. I mean it becomes inaccessible. Then I cose the second modal dialog, The original modal dialog is still blocked out. As I do it quite long ago it has no such problem. What would be possible I did on it or it's bug from UI? Thank you very much!


Jack