QToolBox looks different then in the designer

问题

I'am using QToolBox, and in the application this widget looks different then in the designer. I'am curious, how i can fix it? OS is ubuntu 14.04 with gnome3.

QToolBox in the app (simple buttons):

QToolBox in designer (has that fancy lines):

来源：https://stackoverflow.com/questions/35482641/qtoolbox-looks-different-then-in-the-designer