gtk:tree-view-hover-expand (object)

object -- a gtk:tree-view widget
expand -- true to enable hover expansion mode

Accessor of the hover-expand slot of the gtk:tree-view class. The gtk:tree-view-hover-expand function returns whether hover expansion mode is turned on for the tree view. The (setf gtk:tree-view-hover-expand) function enables or disables the hover expansion mode. Hover expansion makes rows expand or collapse if the pointer moves over them.