Customizing QTreeWidget's child indicator

I have implemented a custom child indicator for a QTreeWidget as a QPushButton and still in the process of making it look like the original. My question is if anyone knows what control does Qt use for the child indicator, or is it some other control, like a customized QLabel? I have implemented it by sub-classing QPushButton with QPushButton::setFlat(true) and QPushButton::setCheckable(true). But I still see the inflate/deflate behavior of the control when I click on it, just like it happens with QPushButton. So, should I continue styling the button until I get the desired behavior, or should I sub-class another Qt widget instead?