tree.x, tree.y, where tree.x and tree.y are specified
in tree coordinates.  The tree.view must be realized before
this function is called.  If it isn't, you probably want to be
using gtkTreeViewScrollToCell.gtkTreeViewScrollToPoint(object, tree.x, tree.y)objecttree.xtree.ytree.x or tree.y are -1, then that direction isn't scrolled.