Central widgets gets centered after restoring QMainWindow state and geometry

I am on Ubuntu 12.04 64 Bit, using the latest Qt 4.8.1 for Linux from the Qt Website. I have also described the problem here: http://www.qtcentre.org/threads/49183-Weird-behaviour-in-restoring-the-state-and-geometry-of-a-QMainWindow-with-QDockWidget

I have a QMainWindow with several dock widgets and a hidden central widget, because as the documentation states a QMainWindow without a central widget is not supported. Every dock widget has been assigned an object name. Now, when closing the application (and saving the state) and restoring it again, the central widget seems to be centered after a restore again. I made two screenshots attached to this bugreport in order to explain that (before.png before saving, after.png after restoring). The command and current directory dock widgets have been assigned to the right dock widget area and the command window has a minimum width. The workspace and history dock widget have been assigned to the left dock widget area.

You can check the full source here, on branch gui in /gui:
hg clone http://hg.savannah.gnu.org/hgweb/octave/

For, this behaviour is a blocker that prevents us from releasing the Octave GUI. If you have any questions, please contact me directly, I will gladly work with you on solving the issue.