QAbstractItemView style problem

Hi all,
I started from the example SingleItemView from the book "Foundations of Qt Development" by J. Thelin. I'm developing a view made of QComboBoxes, QlineEdits and QCheckBoxes, instead of the QLabel as in the original example.
I've written down my own model for the tree view and works correctly.
Now I'd like to modify the appereance of the right frame, in which there is the content of my model data. I've just added the view elements mentioned before, but the background color of the frame is always white.
I'd like to give to the view widget the aspect of a classic window... Can you give me some hints to do this?

Thanks,
Alex

N.B: i attach the original example hoping there are no problems... If there are copyright problems, tell me and I'll remove quickly the attachment.