The issue can best be seen when running the application through remote connection.
Note! This is a CentOS/RedHat problem only. Cannot be reproduced on Ubuntu.

Steps to reproduce:
1. compile the application and run it remotely via e.g. ssh -X
2. resize the window quickly to smaller and bigger from the corner down right

Expected result:
The window resizes without a delay

Actual result:
There is a delay in the window resizing. There is first an empty frame around the window before it gets caught up and the whole window reaches the boundaries.

The lag in the updating seems to be a feature in CentOS/RedHat platforms, since the same behavior can be seen also with native windows. However it has been smoother in Qt 4.7.5 and the issue can be reproduced from Qt 4.8.2 onwards at least. So, this is also a Qt regression from Qt 4.7.5.