In TreeView, the behavior of the ScrollBar with QtQuick.Controls.macOS does not follow the native macOS style.

On macOS, when setting the ScrollBar.vertical and ScrollBar.horizontal properties for TreeView, using the QtQuick.Controls.macOS style for the ScrollBar does not follow the native macOS behavior, such as automatically hiding when not scrolling or enlarging on hover. The scrollbar remains visible at all times, and it does not enlarge when hovered over. Testing with other styles of QtQuick.Controls’ ScrollBar shows that they follow the native behavior of automatically hiding.

ps: tested only in the TreeView view, not tested elsewhere.