Qt Creator cannot display QHash's content while debugging

Hello,
I am using Qt Creator 1.3.1 with Qt 4.6.2(32 bit) on windows 7.
While debugging, I can see the number of elements in a QHash item on the value field; but when i click on the item to see its contents, in the value field it says "not in scope".
What may be the problem?

Thanks in advance...