It is "QScrollBar" not "QscrollBar".
http://doc.qt.io/qt-5/stylesheet-exa...ing-qscrollbar provides full examples and comes with the note that if one property or sub-control is customized, all the other properties or sub-controls must be customized as well.

http://doc.qt.io/qt-5/stylesheet-exa...zing-qtreeview shows how to replace the branch open/closed icon and lines with images in a QTreeView.