QToolBar shows weird artifacts in the background on Ubuntu 12.04
===

I'm having a bit of a problem with QToolBar. It's only a graphic thing and although it doesn't create problems it's quite annoying. I've created my custom widgets with QtDesigner and I have a QToolBar that I place in Qt::RightToolBarArea. I set the widget of my toolbar to be the custom widget I mentioned above. All like this:

    myToolBar = new QToolBar();

    myWidget = new MyWidget();
    myToolBar->addWidget(myWidget);

    myToolBar->setMovable(true);
    myToolBar->setAllowedAreas(Qt::AllToolBarAreas);
    myMainWindow.addToolBar(Qt::RightToolBarArea, myWidget);

The strange thing is that when I resize the window after a certain value it presents this kind of artifact in the background:

[screenshot][1]

As soon as I reduce the window size after a certain value the background returns normal.

Has anyone encountered such artifacts?

PS: I'm using Ubuntu 12.04 and Qt 4.8


  [1]: http://i47.tinypic.com/30j1yqq.png "screenshot"