How to put a DockWidget or Widget over others??

[dungsivn]

Hi all,

In Qt 4.3, I want to create a small application similar to Slick Edit and have some troubles:

1. Auto Hide feature: how to add a Widget is same as "project" tab or "classes" tab in the left of the Visual Slick application, It means that, when users move over the "Project", "Classes", "FTP" tabs, these widgets will expand slowly and increase its size. The trouble is that when these tabs are increasing its size, these must above the central widget, don't push the central widget to the right. I imitate the way of QRubberband class by using: setAttribute(Qt::WA_NoSystemBackground) method so that the left widget can put over others but it does not affect. How can I do?

2. What should I do to replace the normal symbol on the top-right corner by the auto-hide symbol?

Thanks!