Originally Posted by Muzer
I could have sworn you had to install something (I used to use it on my netbook until a few months ago). Maybe it's just not included in a default Qt installation in Ubuntu and you have to install it because of that?
I wouldn't know how Ubundu packages Qt. When building Qt from source, GTK style is built into QtGui, or optionally as a plug-in. You can test whether it's available quite simply with aforementioned command line option. I think it's -style=gtk
in this case. You can also check KDE's config tool(s) (or otherwise try QtConfig, which, actually probably is a separate package).
Note that I personally never use Linux for desktop use, so I don't know the details of all this, I'm only speaking from general Qt knowledge and things I've heard here and there.