UIDatePicker with white background on item

I have this issue on iOS 7 with UIDatePicker. When I show a UIDatePicker in any view controller it gets a white background on the current date which will disappear if you roll the widget. I've tested with an empty new project with the same result (just new project, set the storyboard color to other than white color and drag any UIDatePicker to the scene and try like this). Does anybody know why is this behaviour? This control is supposed to be transparent and not have this white tag with it.