The bug can be reproduced with the Dir View example on a Windows 10 PC with multiple display configurations. The only code change needed in the example is the change from QScroller::TouchGesture to QScroller::LeftMouseButtonGesture on line 103.

When the application is run the tree view selection with the mouse will not work if the application window is on the primary display. However the selection will work if the application window is moved to a non-primary display. See attached gif.