QGtkStyle: vertical alignment of the text in QTabBar is improper when QGtkStyle is used

Vertical alignment of the text in QTabBar is improper when QGtkStyle is used in application. This doesn't happen in exactly the same situation when Qt or KDE style is in use.

I think it will be best to show screenshots with this bug in action:
1) QGtkStyle in use with default Ubuntu theme, bug exists: http://bit.ly/kCIMc
Wrong alignment marked with red horizontal line. Text/Label is not centred, but is positioned on the bottom of QTabBar.

2) KDE style in use, Oxygen theme. Bug does not exist: http://bit.ly/1m5fcS
Proper alignment marked with red horizontal line. Text/Label is centred as expected.

The same bug is present with all GTK styles reused by QGtkStyle:

• GTK Crux style, bug exists: http://bit.ly/2WmGtM
• GTK Dust style, bug exists: http://bit.ly/4e0vV6
• GTK another style, bug exists: http://bit.ly/3jjuBZ

It is not present with Qt styles:

• Clearlooks, bug does not exist: http://bit.ly/2Ub6uh
• Qtcurve, bug does not exist: http://bit.ly/1a5SX4

Tested on Ubuntu 9.10 with qt 4.5.4 (afaik) with different styles and Kadu Instant Messenger ( http://www.kadu.net )

Do you need any more informations?

regards,
Piotr