Comment 5 for bug 720609

Ah okay. I see better with the screenshot. Effectively, you are on KDE and you are using the GTK2-engine-qtcurve.
At first look (see here : http://openshotusers.com/forum/viewtopic.php?f=11&t=751&p=3696&hilit=rm+gtkrc#p3696), there is a problem with this theme.
And you see that the solution is to remove a hidden folder. After, (but it is not confirm) you should change your theme. IT is to try one time with and after without. And I don't know if you change just the motor-engine before, resolve simply this issue.
So, anyway, you type this in a terminal :
rm .gtkrc-2.0*
and your problem will be resolve.
Thanks.