While using the tabWidget, I have found that there is a small gap between the left end of the screen and the first tab, how ever the third tab touches the right end.
When you set the style sheet so as to make the first tab touch the left end by the following code

tabWidget->setStyleSheet("QTabWidget::tab-bar

\n"
"QTabBar::tab

\n"

it works on the maemo simulator but not on the device or the nokia simulator